Multiple reports now say that U.S. Air Force B-1 Lancers left the United Kingdom over the weekend due to the threat of an Iranian-directed near-field drone attack broadly akin to Ukraine’s Operation Spiderweb that decimated Russian bombers. Though many specific details are still unconfirmed, this is an entirely plausible mode of attack that TWZ has been warning about for many years now.

Short- and long-range drone threats against parked aircraft have now morphed fully from theory to reality, as also demonstrated by losses in the course of the conflict with Iran, and even non-state actors are increasingly brandishing these capabilities. Despite the increasing dangers posed to planes out on open flightlines, the Pentagon continues to drag its feet on building hardened aircraft shelters and other fortified air base infrastructure.

Before the hasty and unexpected departure of the bombers on Sunday, B-1s had been deployed to RAF Fairford continuously since March, initially in support of Operation Epic Fury against Iran. A contingent of B-52s had also conducted strikes on Iran from Fairford, but left back in July. The base is a major operational hub for the U.S. military in the United Kingdom, and regularly hosts strategic aircraft, including bombers and U-2 spy planes.

Dan Rivers, U.S. correspondent for ITV News in the United Kingdom, was among the first to report on Monday that the B-1’s quick departure had been prompted by concerns about a potential Spiderweb-like drone attack ordered by Iran, citing an unnamed source. Other outlets have subsequently reported similar details, all sourced to anonymous U.S. and British officials.

Ukraine’s unprecedented Operation Spiderweb last year involved simultaneous covert near-field attacks using explosive-laden quadcopter-type drones on airbases across Russia. At least 10 Russian bombers, as well as a variety of other aircraft, all parked on open flightlines, were destroyed.

“They didn’t fly out by accident,” U.S. President Donald Trump told reporters during a gaggle at the White House on Monday when asked about why the B-1s had left Fairford. “There were some threats.”

“I can’t tell you that, but if they did, they’ll suffer greatly,” Trump added in response to a separate question about whether Iran might have managed to get weaponized drones into the United Kingdom.

“What you saw there was the Secretary of War [Pete Hegseth], out of an abundance of caution, trying to protect our guys,” U.S. Vice President J.D. Vance said during a separate press engagement on Monday. “We do feel, with some confidence, that the Iranians are – they’re trying to do what the Iranian state has done for 49 years, which is engage in acts of terrorism against the United States, and a lot of other people, as well. So, we are being extremely cautious.”

It’s also worth noting here that British authorities had arrested five men on suspicion of driving bomb-laden vans toward the base back on September 27. Those individuals were released on bail after no explosives were found in the vehicles. U.S. and British officials have also raised the possibility of an Iranian link to that incident.

“We’ve documented what happened [near Fairford] last week. I wouldn’t just directly tie that to the move that was made,” U.S. Secretary of State and National Security Advisor Marco Rubio also told members of the press on Monday. “The only reason why you guys are focused on how many planes are at Fairford is because of the threat that happened last week.”

“We have confidence in the security of all of our bases, because all of our bases are [sic] theoretically could be threatened at any moment,” he added.

Rubio’s comments notwithstanding, the remarks from Trump and Vance make clear that there was some recent threat intelligence that contributed to the decision to pull the bombers from Fairford. There are still many questions about the exact nature of the potential attacks, and how imminent, or not, the danger may have been.

Regardless, as mentioned, the prospect of a near-field drone attack on a base like Fairford carried out by actors in close proximity is extremely plausible, and the barrier to entry to such an operation is relatively low. Spiderweb may have thrust this reality into the public consciousness in dramatic fashion, but the danger well predates that operation, and even the start of Russia’s all-out invasion of Ukraine in 2022.

TWZ has been highlighting exactly these kinds of threats in the course of a decade or so now of regular reporting on drone incursions over U.S. and foreign military facilities and critical infrastructure, as well as American naval vessels operating offshore. Langley Air Force Base in Virginia and Barksdale Air Force Base in Louisiana, some of America’s most strategic airbases domestically, are among the facilities that have had to grapple with this in the past. After the Langley incident, in particular, it had become clear to the larger public what we had been reporting for many years, that the United States does not control the airspace over even its most critical military installations.

This all extends overseas, as well. In November 2024, there was a rash of drone sightings over and around several airbases in the United Kingdom, including RAF Fairford. This has been an issue more broadly in Europe in recent years, as well. This was only further underscored by an attempted drone attack on a Ukrainian An-124 at an airport in Germany in August, which authorities in that country have blamed on Russia.

New footage of yet another act of Russian terrorism on EU soil, showing the drone loaded with explosives on the tarmac at Leipzig/Halle Airport, just meters from a Ukrainian Antonov An-124 cargo aircraft.

According to German authorities, the drone was carrying an improvised… https://t.co/eCZaLfz9yx pic.twitter.com/DbRz87wgIv

— SPRAVDI — Stratcom Centre (@StratcomCentre) August 5, 2026

A drone attack on Fairford would also not necessarily have had to come from somewhere very close by. Longer-range one-way attack drones are steadily proliferating, and can be launched using a variety of methods from positions on the ground, as well as vessels at sea. TWZ explored the very real threat of sea-based drone attacks, including ones conducted covertly, and Iran’s specific ability to carry them out globally, following the leak of an FBI alert back in March.

The proliferation of lower-end one-way-attack drones has ‘democratized’ precision-guided attacks, even for non-state actors. The fielding of automated targeting capabilities, driven by developments in artificial intelligence and machine learning, is also becoming more and more widespread. That technology will soon enable these weapons to find and strike even moving targets on their own. Even without anyone at the controls and without the drone putting out any detectable radio emissions, very effective precision attacks can still be launched at static targets, like known parking areas for aircraft at airbases, just by using basic map coordinates or Google Earth. It’s also worth pointing out here that the definition of a stand-off attack is becoming increasingly blurry, with even quadcopter-type drones capable of flying miles away to conduct a kamikaze attack on a target based on a set of GPS coordinates.

Ukrainian Saker UAV with AI capabilities. The video shows the process of target recognition. It has reportedly already been put to use several times against Russian targets. pic.twitter.com/NVNJyxUjGP

— NOELREPORTS (@NOELreports) January 25, 2024

Overall, it is an indisputable fact that aircraft sitting exposed on a flightline are particularly vulnerable to drone attacks, as well as other threats. This is something U.S. military officials have acknowledged themselves. Fairford, where B-1s and other bombers have no option but to park out in the open in well-established areas that are plainly visible from outside the base’s immediate perimeter, is indicative of how American military aircraft are generally positioned on the ground abroad and at home.

As we wrote all the way back in 2017:

“Similar swarming strikes could be unleashed behind the front lines as well, with hugely expensive and low density/high demand combat aircraft being especially vulnerable to this sort of tactic—something General James Holmes alluded to inadvertently while speaking to the Air Force Association, stating:

‘Imagine a world where somebody flies a couple hundred of those and flies one down the intake of my F-22s with just a small weapon on it.’

Actually, it would be even easier to just strike the jets as they sit idle and vulnerable on the flight line. One swarm could see a whole squadron of tightly packed fighters destroyed without even having a chance to fight back.”

With all this in mind, a heated debate has emerged in the past few years in and around the U.S. military about the value of investing in new hardened aircraft shelters, as well as other fortified infrastructure.

To date, the U.S. Air Force, in particular, has put virtually all emphasis on surface-to-air missiles and other active defenses, as well as the dispersal of aircraft, over physical hardening. The conflict with Iran, in which a number of American military aircraft have been damaged or destroyed on the ground by drone and missile attacks, has underscored the limits of these strategies.

Second angle. pic.twitter.com/NUupdRkdm9

— OSINTtechnical (@Osinttechnical) March 29, 2026

“I’m not a big fan of hardening infrastructure,” Gen. Kenneth Wilsbach said at a roundtable at the Air and Space Forces Association’s main annual symposium in 2023, offering a prime example of this viewpoint. “The reason is because of the advent of precision-guided weapons … you saw what we did to the Iraqi Air Force and their hardened aircraft shelters. They’re not so hard when you put a 2,000-pound bomb right through the roof.”

Wilsbach was commander of Pacific Air Forces (PACAF) at the time. He subsequently became head of ACC and is now Chief of Staff of the Air Force, the service’s top officer.

“I think that I don’t want to spend a lot of money on hardening shelters. Unless you’re going to send something 100 feet or more underground, we can blow it up, and so can they,” Wilsbach said in an interview with Breaking Defense in July of this year when asked explicitly if his position changed. “So, the economics of building a shelter that is impervious to a strike doesn’t work.”

“I think the economics favor defending your airspace, defending your ground space with systems that can defeat the incoming rounds, versus building a shelter,” he added. “Some people would argue, well, you should do both. Well, that’s even more expensive. And the other thing is, the shelter doesn’t go anywhere.”

It is fair to point out that typical above-ground hardened aircraft shelters are not invulnerable, especially to attacks involving ballistic, cruise, and certain air-launched threats. There are also substantial cost and other factors to consider when it comes to any major military construction effort.

That being said, having more hardened infrastructure also imposes costs and complexities on opponents, who have to dedicate more advanced and costly munitions and other resources to ensure targets are neutralized. Shelters have the knock-on benefit of complicating the targeting process for an enemy by obscuring where aircraft are or are not positioned, to begin with. An opponent has to treat shelters like they are full even if they are empty.

When thinking about hardened aircraft shelters, stereotypical Cold War-era reinforced concrete structures typically come to mind. However, they do not all have to be built to a one-size-fits-all standard with the same degree of hardening across the board to be useful. Shorter-range drone attacks are typically carried out by platforms carrying small explosive charges or that are designed to drop small bomblets. Even longer-range one-way-attack drones generally have smaller warheads than traditional missiles, they also hit with less kinetic energy.

A structure that shields against smaller blasts and shrapnel, also including from cluster munitions that can be readily scattered across wide areas, is one that then has to be addressed by more capable weapons. This could even include mobile or otherwise temporary shelters that offer sufficient concealment and protection.

Eliminating, or at least substantially mitigating, the lowest rung of threats creates a dilemma for opponents, who then have to decide whether it is even worthwhile to attempt certain types of attacks. There is clear value in narrowing the available options for the enemy and pushing them toward having to expend higher-end, more expensive munitions, that are available in smaller quantities, and that traditional active defenses may be better optimized to handle. As an example, it may be more viable to shoot down a small barrage of incoming cruise missiles than a swarm of dozens of drones.

Active defenses, especially surface-to-air missile batteries and interceptors to go with them, have historically been very expensive. Lower-end counter-drone-focused interceptors and directed energy weapons are helping to bring these costs down in some regards. Even so, those capabilities come at a significant cost.

There are magazine and stockpile depth issues at play here, too. This is something that has also been brought front and center by the conflict with Iran, which has fueled already long-standing concerns about the sufficiency of stockpiles of air defense interceptors, other critical munitions, and the capacity to replenish them quickly. This is something the British government, among others, is also grappling with, as you can read more about in our separate reporting here.

Furthermore, losses of aircraft on the ground are not without their own costs, which are even more lopsided if an opponent can simply use lower-cost weaponized drones. U.S. bombers are particularly expensive and prized assets that are in short supply compared to the level of demand, as seen during the height of combat operations earlier this year against Iran. When it comes to B-1s, specifically, there are only 45 of them left in service today. A dozen of them being knocked out in one go would have major repercussions strategically. Losing even one would also be a propaganda coup for whoever might be responsible.

How many shelters can we build for the upgrade cost of one Zumwalt class DDG that will probably be parted out in 10 years anyway?

— Tyler Rogoway (@Aviation_Intel) October 5, 2026

On top of all this, the U.S. military simply will not always have the luxury of being able to rapidly relocate aircraft in response to threats. Moving a dozen bombers on short notice takes massive resources. It is not just aircraft that have to be repositioned, but supporting personnel and assets, as well as weapons and fuel. Having to shift to alternate locations could easily have negative impacts on tempo and other aspects of operations, especially in the midst of actual conflict. RAF Fairford is one of only a few bases globally that can support bomber operations for a prolonged period.

More recently, there have been signs of changing mindsets on the matter of hardening across the U.S. military. In January, Joint Inter-Agency Task Force 401 (JIATF-401), a focal point for counter-drone efforts the Pentagon established last year, issued explicit guidance regarding the use of netting, cables, and other kinds of passive physical defenses around bases and other critical infrastructure. A contracting notice in March also called attention to plans for new hardened underground facilities at Al Udeid Air Base in Qatar.

“There is value in some light protection against small, unmanned threats,” Gen. Wilsbach also told Breaking Defense in July. “Some of them — just nets that are up that keep a small, few-$100 drone from getting next to a $2 billion aircraft. That actually works, [and is] really cheap.”

“It’s not either or,” Wilsbach said in a separate interview with Air & Space Forces Magazine in July. “The net keeps the small UAS [uncrewed aerial system] from getting close to an aircraft that you’re trying to protect… That’s a very inexpensive way to give you some modicum of protection without killing your checkbook on really exquisite defensive systems.”

In spite of these institutional developments, action to implement such recommendations on a broad basis has continued to lag. There still does not appear to be any major department-wide push to build new hardened aircraft shelters or other fortified structures at facilities globally. The U.S. Air Force does have a certain number of hardened aircraft shelters at bases now, especially in the Pacific and Europe.

This is all despite a very visible trend in the construction of new aircraft shelters and other hardened infrastructure elsewhere around the globe, including in China, Russia, North Korea, and Iran. Even before Operation Spiderweb, Russia had already initiated a large-scale effort to build new hardened shelters at various bases, especially on the occupied Crimean Peninsula, in the face of expanding Ukrainian drone and missile attacks. This effort has now extended to building the huge hardened shelters for the country’s bomber force, something the country has never done before.

“It is inappropriate to discuss matters of intelligence, and we will not discuss specific force protection measures,” a U.S. Air Force spokesperson told TWZ yesterday when asked about the reports that Iranian drone threats prompted the recent removal of the B-1s from Fairford. “The Department will continue to assess the threat environment surrounding our installations and take appropriate actions to protect our people, our platforms and the bases where our forces operate from.”

We still do not know exactly how serious or imminent any recent threat to the B-1s at Fairford was that contributed to their hasty departure. Regardless, the reports of concerns about potential drone attacks remain very plausible. The reality here is that a dozen bombers were yanked from a forward operating location in Europe without an adversary ever having to fire a shot. This is a problem set that is only growing, especially as lessons and expertise on low-end weaponized drones from the war in Ukraine are spreading around the globe.

Erecting new aircraft shelters and other hardened infrastructure would not be a full solution to those threats by themselves. At the same time, they would be a valuable added layer of defense, and a passive one that would have a huge logistical footprint to operate once the initial investment is made. The lack of movement to better fortify American airbases globally is only becoming more and more glaring, and it remains to be seen if real action will not occur until lessons are learned in a most unfortunate way.

Contact the author: joe@twz.com

The post Glaring Lack Of Investment In Aircraft Shelters Highlighted By B-1B’s Sudden Retreat From U.K. Airbase appeared first on TWZ.

During his time as the lead propulsion engineer for SR-71 Blackbirds at NASA’s Dryden Flight Research Center, Tim Conners looked into how to push the iconic recon plane to fly faster than it had ever flown before. The world record for any crewed jet-powered aircraft is officially Mach 3.3, or 2,193 mph. It was set by a Blackbird in 1976 “on a straight-line course over Edwards Air Force Base in California.” In a recent interview with TWZ, Conners said he investigated whether there were ways to get Blackbird to approach Mach 4, equivalent to roughly a whopping 2,660 mph at altitude. Fast forward to today, with the possibility that NASA could be returning the SR-71 in some configuration to its test fleet, as well as its potential missions, the question of just how fast could the airframe go has become far more relevant than just a hypothetical exercise.

Conners spoke to us about his knowledge of plans to restore SR-71 #844, which had mysteriously disappeared from NASA’s Armstrong Flight Research Center, as well as its potential uses, in a deep-dive interview here. Prior to the revelations about the missing Blackbird, speculation about NASA’s renewed interest in the type was sparked last month, when NASA Administrator Jared Isaacman showed the silhouette of an aircraft that immediately drew comparisons to SR-71 during a speech at the annual All-In Summit in Los Angeles, California. Isaacman pushed back on a direct link to the SR-71 but said his agency is working hard to get “back in the business of flying high and fast again.”

Given that, we wanted to know what limited the SR-71’s speed in its original configuration and how fast Conners thought it could go with modifications.

“The study that I did at Dryden was purely conceptual,” Conners explained of his work on the topic there in the early 1990s. “I asked questions of the Lockheed folks and the Pratt folks regarding limitations on speed. So stagnation temperature. What can we get to at altitude?”

The Blackbird, he said, “flew a trajectory that was usually operationally limited to 450 knots equivalent airspeed. If you look at the flight envelope, that defines the right edge of the envelope.”

“The engines, however, were optimized to fly at about 500 knots equivalent airspeed, 475 to 500, and for whatever reason, there was a mismatch between what the engines were designed to do and what the airframe was ultimately optimized for, which was flight at around 450 knots,” the engineer added. “And you end up with that limitation now, the equivalent airspeed curve hooks up and to the right as you go up in altitude, so it sweeps out Mach number, and as you sweep out Mach number, the stagnation temperature is going up on you.”

“So you do reach a point, even at 500 KEAS [knots equivalent airspeed], where you end up with a constant value up at altitude once you’re in the stratosphere,” Conners said. “The Blackbird was trimmed or limited at that speed on the right side of the envelope, and that equated to a certain stagnation temperature. That limitation was driven primarily by the material strength of the engine front frame, from what it was described to me, and that’s what drove the analysis we did at NASA.”

To even consider pushing the aircraft past the world record speed, Conners said something had to be done to mitigate the tremendous effects of the extreme heat on the air entering the engines.

“We weren’t looking at active cooling of the frame by pumping coolant through it,” Conners recalled. “What we looked at was spray cooling of the incoming airflow to lower the bulk temperature, so it would only be used when you were accelerating beyond about Mach 3.4. You would only very briefly do Mach excursions to a higher Mach number, and then come back. That was the conops for that system.”

“This is a way to [get to a higher Mach range] briefly,” the engineer postulated. “You could probably get to a higher Mach number. The problem is that if you clog or freeze the system, if it fails while you’re at higher speed, you have to decelerate in a hurry to protect the assets.”

Among other impediments to breaking the speed record, the Blackbird’s existing power plant was not up to the job, according to Conners.

“So that weak link was the J58,” he explained. “It had the performance, but not the material strength. If we’re looking at alternate engines designed to handle the higher Mach capability, then that could put the limiter on the airframe at that point, which we were told at NASA was somewhere like up near Mach 4 for brief excursions.”

Aviation expert Paul F. Crickmore, who’s written several books about the Blackbird, told us that the aircraft was designed around a sustained cruise speed of Mach 3.2, with the primary critical limitation being aforementioned compressor inlet temperature (CIT).

Above 427 degrees Celsius (about 800 degrees Fahrenheit), the engines would be damaged, Crickmore noted. But if outside air temperature was colder, the aircraft could go faster before hitting that limit (in practice, Mach 3.3).

Temperature was just one factor in limiting how fast the SR-71 could travel, Crickmore explained. The shock waves from traveling so fast would also tamp down the Blackbird’s ultimate speed potential.

“On the SR, you have to think three-dimensionally,” Crickmore explained. “But looking in just two dimensions, you would have an oblique shock wave on the nose, the first shock wave, and it would be at 90 degrees on either side. As the airplane got faster, that cone became more sharp until you got down to about 32 degrees. Now, at that speed, you’re at [Mach] 3.2. That oblique shock wave was still outside the envelope of the airplane – you don’t want to get that shockwave going anywhere near the flight controls. The faster you go, the narrower that cone, and the closer it gets to the wingtips, which is not good. This is the thing: People say, ‘Oh yeah, we can go maybe Mach 6.’ Well, right. But it’s not just about that. It’s about a lot of other things.”

The limiting factors imposed by the CIT value and the shockwave effect are also recalled by the late SR-71 pilot David Peters, recounted on the Habubrats SR-71 account on X.

“A little clarification on the speed. The issue is that I have been limited to less than Mach 3 on a few occasions because the outside air temperature was entirely above standard, and 427C came up at about [Mach] 2.95. On other occasions, like the Murmansk deal I got above 3.4 (3.49 on one occasion) and wasn’t close to 427C. The actual limiting airspeed is around 3.55; that is where the spike, being at full retraction loses the intercept on the shock wave and can no longer position it correctly in the inlet. Also, the overflow of the shock starts to go over the wing and interfere with the flight controls. So the limiting speed as configured would be about 3.55 so long as you don’t exceed 427C.”

For his part, Conners said that “shock effects at the inlet can be accommodated through rescheduling the inlet spike movement and perhaps making changes to the bypass schedules. None of that would necessarily be simple, and any changes would require careful envelope expansion. But it would not be impossible.”

Regardless of any other factors, Conners, the Blackbird engineer, remembered that his effort in boosting the jet’s speed never took off.

“It never got beyond me just sizing tank volume, considering different fluids that might work as a coolant, and then just gauging the relative appetite of NASA hierarchy for something like that,” Conners stated. “They weren’t interested in the risk. Nobody was asking for that Mach range.”

But that may be changing. It seems clear that one of the biggest challenges of getting the Blackbird back in the air will be its engines. They have sat for a long time, and getting them into a flyable condition could be the limiting issue. Beyond that, equipping the SR-71 with new engines also may represent the biggest opportunity for NASA getting a return on investment from its revived Blackbird.

In our interview, Conners told us that the feedback he heard about the remaining Blackbird J58 engines was “discouraging” because “the engines are indeed unserviceable.”

“I don’t believe that is based on an actual attempt to run them,” he explained. “It is based on inspection. Probably no surprise. They’ve sat idle, you know, for 27 years. That is what led to questions going back and forth regarding how the airframe would be powered. And that’s what led into, if you connect the dots, that’s where the airframe would be used as an engine test bed.”

Different engines “would have to be high-Mach bypass systems,” he noted. “We can speculate on which engine company might be developing those systems, but yeah, I don’t want to give it too much away because I don’t want us to lose the inside information that we got.”

Also, the flight regime approaching Mach 4 would likely be one of the areas NASA is most interested in. It’s here where a combined cycle engine capable of hypersonic flight, one that contains both turbojet and ramjet or scramjet functions, would ‘hand-off’ propulsion from the turbojet to the other that is optimized for extreme speed. This is the same concept behind Lockheed’s SR-72 concept. Having an aircraft, and especially one that is not mired in deep classification and hidden from view, that can actually test this transitional flight regime could be of extreme value in unlocking a future where hypersonic flight is more accessible.

“Yeah, that could very well be what we’re looking at here,” Conners told us when we asked whether Blackbird’s open classification level is a driving factor in using it as a test bed for this research. “I’ve had friends ask that question this week. We were talking about the SR-72. Where is that at? I don’t know. I know people who went to work on it years ago. I’ve never heard anything since. So it could be that that’s so deep black that there’s no way that platform could be used as a test asset. So I think it’s precisely what you said. The Blackbird’s no longer classified, and that it’s possible that the engines that might be used in Blackbird wouldn’t be classified either.”

So, reengining the SR-71 may solve two birds with one stone — providing a modern powerplant that won’t require the J58s to be revived and taking care of the inlet temperature issues discussed above that would allow the SR-71 airframe’s full potential to be exploited in testing. The fact that the jet can carry a massive payload on its back could allow it to provide critical testing of the handoff for dual cycle engine concepts.

This is just one use, of course. With the explosion in high-speed flight for defense purposes over the last decade, there are many other reasons to push a Blackbird to higher Mach numbers.

So with all this in mind, if we get the Blackbird back at all, maybe it will roll out with some major modifications that could indeed push it to new velocities.

Contact the author: howard@twz.com

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