Title: The Air Force’s Aerial Refueling Fleet Is Shrinking in Capability Description: During long flights or extended air combat missions, aerial refueling tankers can eliminate the need for military planes to land. Having this capability is vital for some missions, like rapid long-distance strikes or when landing to refuel isn't safe. The U.S. Air Force maintains the world's largest fleet of aerial refueling tankers. But even so, the condition of these planes and the Air Force's ability to maintain them may not meet the military's needs. Learn more from GAO’s Diana Maurer. Related work: GAO-26-109154, Aerial Refueling Tankers: Air Force Needs More Focused Metrics and a Risk-Based Mitigation Plan to Improve Sustainment Released: June 2026 {Music} [Diana Maurer:] The Air Force needs a healthy fleet of refueling tankers to support critical military operations around the world. [Holly Hobbs:] Welcome to GAO's Watchdog Report. Your source for fact-based, nonpartisan news and information from the U.S. Government Accountability Office. I'm your host, Holly Hobbs. During long flights or extended air combat missions, aerial refueling tankers can eliminate the need for military planes to land. Having this capability is vital for some missions, like rapid long-distance strikes or when landing to refuel isn't safe. The U.S. Air Force maintains the world's largest fleet of aerial refueling tankers. But even so, the condition of these planes and the Air Force's ability to maintain them may not meet the military's needs. Here to tell us more about this issue is GAO's Diana Mauer. Thanks for joining us. [Diana Maurer:] Thank you. It's wonderful to be here. [Holly Hobbs:] Diana, maybe we could start with, what do these aerial refueling tankers allow the military to do, which they couldn't otherwise if they didn't have them? [Diana Maurer:] Sure. So, refueling tankers are basically like flying gas stations. They allow the U.S. military to fly aircraft further and longer than they otherwise would be able to without having to land. What that means is, for example, U.S. bombers can take off from the United States, fly 7,000 miles or more to the Middle East to perform a mission and come back without ever having to land. Fighter aircraft can stay up in the air for hours on end to defend positions, and this gives the U.S. state-of-the-art capabilities that other countries simply do not have. [Holly Hobbs:] What kinds of missions have these planes been used in? [Diana Maurer:] So tankers can actually perform multiple missions. Their main mission, of course, is refueling other aircraft. But they can also be used to move personnel, medical evacuations or carry cargo. But they are the only aircraft that can do refueling. There are other planes that can do cargo missions, but only tankers can perform the refueling mission. [Holly Hobbs:] And how do they work? [Diana Maurer:] So this is a very precise and delicate operation. Think about if you were driving in your car on the interstate. You're a passenger and you decide, ‘Hey, I'm gonna hand a sandwich through the window to the car next to me.’ You might even be nervous even thinking about that as a possibility, because it's a very dangerous thing to do. Aerial refueling involves doing that thousands of feet in the air between two aircraft that are moving at hundreds of miles an hour. The pilots of both aircraft need to be moving in precise synchronization to allow the refueling tanker to have the connector from the refueling plane to the receiving plane connect and allow the fuel to flow. It's very difficult, it takes a lot of training. In the videos that you watch of the Air Force pilots doing this, they make it look very, very easy. But that's because they are very skilled and they have a lot of practice in doing this. [Holly Hobbs:] We said the Air Force has the largest fleet. How many does it have? [Diana Maurer:] As of March of 2026, the Air Force had about 470 or so refueling tankers. Most of the fleet, about 370 or so, are of the older model KC-135s, and a little over 100 are of the newer model, the KC-46. Now, over time, the proportion of the fleet that's made up with the newer aircraft is going to increase. Congress has set, by law, the minimum number of refueling tankers that the Air Force can have. And so, by October of 2028, they have to have at least 502. And a larger proportion of that fleet will be the newer model KC-46 than is currently the case. [Holly Hobbs:] You said the Air Force has two different types of these planes. What's the difference between them? [Diana Maurer:] So the 135, the older version has been flying since the 1950s. What that means is that the pilot and the crew of these aircraft are substantially younger than the plane that they're actually flying. And this system has been the backbone of the U.S. military's refueling capability for decades. But the Air Force decided, ‘You know, maybe flying a plane for 60 years, it’s time to get a new version.’ So they decided to purchase the KC-46. This is a very new aircraft. It's based on a commercial refueling tanker that U.S. airlines use, for instance, entered into service in the Air Force in 2019. It has some capabilities that the older KC-135 does not have. Both aircraft, though, have the ability to connect with different kinds of aircraft and provide fuel. The boom system, which is what the Air Force uses to connect fighter jets with a refueling tanker—both the refueling tankers have the ability to do that. The second way that they connect is through what's called the hose and drogue system, which is what the U.S. Navy and a lot of our allies use. So, sort of think about iPhones and you have Android phones with different connectors. It's exactly the same thing here. Both aircraft can use both connectors to connect with both types of aircraft. One key difference, though, is that the KC-135, the older version, has to land to swap out its connectors, which is inconvenient. The KC-46, the newer version, does not have to land to swap it out, which means it can refuel different kinds of aircraft without having to land. It can even refuel two airplanes at the same time. In addition, in the older aircraft, when the operator is guiding the boom or the drogue into the plane that's receiving the fuel, they're lying on their belly inside the aircraft while the pilot maneuvers the plane to dock so it can dock. On the newer aircraft, the boom operator or the drogue operator is sitting at a terminal in the aircraft. They have much better visibility and much more control as they're connecting. So, the KC-46, since it's newer, has some additional capabilities. [Holly Hobbs:] It's 3 to 1, the older planes? [Diana Maurer:] Currently, yes. [Holly Hobbs:] Are there plans to retire those planes? [Diana Maurer:] Yes. The Air Force, at some point, is going to retire all of the older planes. Under their current plans, they are thinking about flying that aircraft into the 2050s, which means it could be flying for almost 100 years, which is pretty remarkable. But over a period of time, more and more of the fleet will be made up of the newer aircraft. [Holly Hobbs:] One of these planes was recently involved in a crash. What can you tell us about that? And did our work touch on any of the topics that, you know, might have caused that crash? [Diana Maurer:] Sure. So, in March of 2026, two KC-135 collided in mid-air over Iraq. And they're involved in ongoing military operations against Iran. Now, what the military has said publicly is that it was a collision. And tragically, all the crew members on the plane that crashed perished. But the military has not provided an official explanation as to why the planes collided. In addition to that collision, the Iranians have damaged based on public reporting, five or six other refueling tankers on the ground so that the overall size of the fleet has been diminished a bit. [Holly Hobbs:] Congress asked us to look at this issue because there were concerns that these planes would not be ready for use when they were needed. And now we have five fewer of them? We looked at the military's efforts to sustain these planes. What did we find? [Diana Maurer:] We looked at how frequently these aircraft were available to perform their assigned missions. And there's different ways of measuring that. But we found for both systems—the older plane as well as the newer plane, going back to 2019—that neither system met the Air Force goals for mission capability or availability in any year. Furthermore, the planes’ ability to achieve all of their missions what's known as full mission capability, has declined significantly over the course of the time period that we looked at, which was 2019 to 2025. And this is, raises a lot of concerns about the overall ability to sustain and operate the aircraft. [Holly Hobbs:] Do we know why that's happening? [Diana Maurer:] The team that did this report looked very carefully at that, and we went out and talked to representatives at Air Force bases around the country. We found a whole host of sustainment problems for both systems. We found problems in four main areas. First, there was a real problem with lack of spare parts, just not enough spare parts. And often there were delays in getting needed spare parts because there are either not enough vendors making those parts or, in some instances, no vendors to make those parts. Because remember, the KC-135 is 60 years old. So, some of the original vendors have long gone out of business. Second problem we found was that there were not enough trained maintainers in the Air Force. There are enough people who are in those positions, but they hadn't received the sufficient level of training to perform the necessary maintenance. Third problem was with infrastructure, specifically hangar space for the newer aircraft, which are configured a little bit differently and they’re larger. So, we found that there are problems with modernizing hangars to allow the KC-46s to actually fit so they could be repaired. That means the Air Force is leaving aircraft outside where they're exposed to the weather and the elements. The fourth problem we found was in the in the realm of technical data, which are things like repair manuals and access to intellectual property, so that uniformed personnel can fix both aircraft. For the KC-46, I think what you mentioned before, that's a military version of a commercial aircraft. When the contractor delivered the aircraft, they provided the Air Force the civilian repair manuals, which don't work very well because the Air Force uses the KC-46 under very different conditions with very different operational tempo than in the civilian sector. So, we found that maintainers in the Air Force have developed these informal networks to trade knowledge on how to fix the airplane. They do that because they can't rely on the manuals that the contractor provided. So, a whole host of problems. [Holly Hobbs:] So when it comes to sustainment, what more do we think the Air Force should be doing? [Diana Maurer:] So the Air Force, to its credit, we found, is taking action to address all of these problems that we laid out in the report. But the challenge they're facing is that there are so many problems that they need to take a more strategic look. And so, we found and we recommended that the Air Force take a holistic approach to assessing the risks of all the different sustainment problems and focus on correcting those areas that will allow them to improve mission capability the fastest at the lowest costs. So do just a systemic look at all these different problematic areas and focus on the ones that give them the biggest bang for the buck. [Holly Hobbs:] Last question. What's the bottom line of our report? [Diana Maurer:] The Air Force needs a healthy fleet of refueling tankers to support missions around the globe. We found a number of sustainment problems with both systems. It's important for the Air Force to take a holistic approach to addressing these problems. Doing so will enhance their ability to help support and perform critical military operations around the world. {Music} [Holly Hobbs:] Diana, thanks for your time. [Diana Maurer:] Thank you very much. [Holly Hobbs:] And thank you for listening to the Watchdog Report. 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