WASHINGTON — The U.S. Air Force is on track to begin permanently basing its F-35 jets abroad next year, with RAF Lakenheath in England set to become the service’s first international F-35 base. But construction on new hangars and facilities necessary for supporting the high-tech stealth jet have gone over budget and over schedule, and many buildings won’t be ready when the first planes arrive in November 2021.

On average, construction projects associated with the F-35 beddown at Lakenheath are about 25 percent over the initial $480 million budget estimated in 2015, said Lt. Col. Clinton Warner, who leads the 48th Fighter Wing’s F-35 program integration office.

“The overall trend has been projects are late and also over budget,” he told Defense News during a July interview. “A lot of the assumptions that were made back in 2015 weren’t necessarily valid. There’s been cost growth that was outside of the planning assumptions that were made back in 2015.”

The cost increase is not the only problem. As RAF Lakenheath’s first F-35 squadron stands up, neither the hangars planned to house the jets nor the headquarters building used for planning operations and maintenance will be ready, Warner said. A training simulator building will also be late.

Despite the delays, the Air Force still plans to move forward with the beddown of the jet. Warner said the service is exploring options to keep operations on track, such having the new F-35 squadron share space with existing units — which include three American F-15 squadrons — or potentially leasing additional facilities on base from the United Kingdom.

“In terms of getting here and flying the aircraft, we will still do that. [There is] really no difference in terms of the capability is going to be delivered, but it’ll just look different in how we do it,” Warner said. “It will be some strain on the units here at the base, as there’s more crowding and with waiting for those facilities to come online.”

The arrival of U.S. Air Force F-35s in Europe has been a long-awaited milestone for the service, which announced in 2015 that RAF Lakenheath would become the first international location to get the jets. Since then, F-35s temporarily deployed to the base in 2017.

“Having a fighter with the capability of the F-35s one hop closer to a part of the world that’s seemingly less stable certainly will have a deterrent effect,” said Frank Gorenc, a retired four-star general who commanded U.S. Air Forces in Europe from 2013 to 2016.

“Being able to daily train with the partners that have F-35s will have a deterrent effect,” Gorenc told Defense News. “It will cause interoperability to soar both on the maintenance side and on the operations side. I think the benefits of having that equipment — the demonstration of having a fifth-generation [fighter jet] in theater combined with F-15Es and F-16s — I think is the right signal.”

Under the current plans, F-35 pilots and maintainers will begin to arrive at RAF Lakenheath in June 2021, with the first aircraft to follow in November. The base will eventually be home to two F-35 squadrons, each with a total of 24 jets.

That beddown will follow more than five years of planning and development on the part of the Air Force, which stood up a team in 2015 to get the base ready for the incoming jets.

Civilian contractors lay down cement at a construction site on RAF Lakenheath, England, on March 9, 2020. The ongoing construction projects will facilitate two F-35A squadrons, making the base the first permanent international location for U.S. Air Force fifth-generation aircraft in Europe. (Airman 1st Class Madeline Herzog/U.S. Air Force)
Civilian contractors lay down cement at a construction site on RAF Lakenheath, England, on March 9, 2020. The ongoing construction projects will facilitate two F-35A squadrons, making the base the first permanent international location for U.S. Air Force fifth-generation aircraft in Europe. (Airman 1st Class Madeline Herzog/U.S. Air Force)

In 2018, the U.S. Air Force chose Kier-Volker Fitzpatrick, a joint venture of U.K.-based design and construction firms Kier Group and VolkerFitzpatrick, to build and renovate all installations associated with the F-35 presence at RAF Lakenheath. Construction began in July 2019, with seven of 14 new facilities — which will include new hangars, a building for flight simulation, a maintenance unit and storage facilities — currently either being built or already complete.

As unforeseen costs have mounted, the base’s program integration office has had to request $90 million in additional funding from Congress, as well as permission from the Pentagon to revise the scope of the projects, Warner said.

But there’s no overarching answer for why costs have ballooned.

“Each individual project had a different set of assumptions, a different set of risk profiles, and some were correct and some are not correct,” Warner said.

With only a few years between the decision to base F-35s at Lakenheath in 2015 and the original planned start of operations in 2020, the U.S. government wanted to put a construction firm under contract sooner rather than later, said Stephen King of the Defence Infrastructure Organisation, a U.K. government agency charged with overseeing the building and maintenance of military facilities.

But workforce costs grew as the project was discovered to be more complex than originally anticipated.

“When the workers are tendered, the prices that are coming back in are found to be different from those originally estimated, and it seems to be the price of doing business on a military establishment. There seems to be an ‘add-on’ to the outside market,” King said.

Because the F-35 is a stealth jet that processes large amounts of classified information, many of the installations linked with its operations must meet certain security specifications. Building those structures to both U.S. and U.K. standards while using a foreign workforce of U.K. citizens posed challenges that the U.S. Air Force did not foresee during the design process, Warner said.

“Luckily most of these problems are behind us, but they did cause delays in terms of when we were programming out in the schedule and looking at what we thought it would look like,” he said. “Some of the challenges associated with building those secure facilities were not fully understood.”

Air Force officials have said keeping the projects on track was always going to be a challenge. In 2016, Col. Robert Novotny, who was then the commander of the base’s 48th Fighter Wing, predicted construction projects could face troubles getting funding or finding a skilled workforce to build the new facilities, and that F-35s likely wouldn’t begin to arrive on base until at least 2021 or 2022.

“For me, the concern I have when I look at Lakenheath is not the F-35,” he told Defense News in July 2016. “For me, the concern I have is: Are we going to be able to build enough stuff fast enough?”