The US Air Force has sent several of its newest stealth fighters to the UK as part of an initiative to reassure Europe in the face of Russian aggression.
A handful of F-35A jets from Hill Air Force Base in Utah landed at RAF Lakenheath over the weekend for what the Pentagon said would be several weeks of training with other US and Nato military aircraft.
The deployment would allow the US Air Force to "further demonstrate the operational capabilities" of the stealthy fighter jet, the Pentagon said.
“As we and our joint F-35 partners bring this aircraft into our inventories, it’s important that we train together to integrate into a seamless team capable of defending the sovereignty of allied nations," said General Tod D Wolters, commander of US Air Forces in Europe.
The jets were deployed in support of the European Reassurance Initiative, launched under President Barack Obama in 2014 to show support for US allies after Russia annexed Crimea from Ukraine.
The F-35, which is the Pentagon's costliest arms program, has been dogged by problems.
The Pentagon's chief arms buyer once described as "acquisition malpractice" the decision to produce jets before completing development.
During last year's election campaign, Donald Trump criticised Lockheed Martin for the F-35's cost overruns.
Days after taking office in January, President Trump announced his administration had been able to cut some $600m (£478m) from the latest US deal to buy around 90 F-35 Joint Strike Fighters.
The United States is expected to spend some $391bn (£312bn) over 15 years to buy about 2,443 of the F-35 aircraft.
F-35s are in use by the US Air Force, Marine Corps and Navy, and by six other countries: Australia, Britain, Norway, Italy, the Netherlands and Israel. Japan took delivery of its first jet in December.
Lockheed said last month that Spain, Belgium and Switzerland were in talks with the company about buying F-35s.
Additional reporting by Reuters
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies