The US has conducted its first mass exercise of its new F-35A fighter jets, launching 52 of them from their base in Utah.

However, the air force insisted it was a coincidence that the number of aircraft used echoed Donald Trump’s threat to hit 52 Iranian targets, including cultural sites.

“Just like the timing, the number is a coincidence. This is the most we can get airborne,” Micah Garbarino, a spokesman at the Hill air force base, said.

The last F-35A Lightning was delivered in December, four years after the first was delivered, bringing the total force of the active duty 388th and reserve 419th fighter wings to 78 aircraft.

Of the three active duty squadrons, one is deployed in the Middle East, leaving two in Utah, which carried out the mass launch – known in the air force as an “elephant walk”.

The exercise represented the achievement of full warfighting capability for the F35, estimated to be the most expensive military program ever, which has been marked by controversies, technical issues and cost overruns.

The F-35A is a conventional takeoff and landing version of the plane. There are also short takeoff and vertical landing, and catapult-assisted takeoff variants.

The US plan is ultimately to acquire more than 2,600 of the planes between now and 2037.

The president has repeatedly expressed a fascination with the aircraft, once telling an audience that the F-35A was “almost like an invisible fighter”.

The F-35A is not invisible, though it is unusually small and designed to be less visible to radar than conventional aircraft.

Trump first startled reporters with talk of an invisible plane in 2017, when he discussed the F-35 at a military briefing in hurricane-hit Puerto Rico.

“Amazing job,” Trump said. “So amazing we are ordering hundreds of millions of dollars of new airplanes for the air force, especially the F-35. You like the F-35? ... You can’t see it. You literally can’t see it. It’s hard to fight a plane you can’t see.”