The first of Australia's F-35 Joint Strike Fighters has been put through its paces in its inaugural flight in the United States.

In a statement, manufacturer Lockheed Martin said its chief test pilot took the aircraft through "a series of functional checks" in a two-hour flight check.

The first of the Joint Strike Fighters (JSF) is scheduled for delivery to the Royal Australian Air Force later this year and will be assigned to an Arizona Air Force base where it will be used for pilot training.

The Federal Government pledged $24 billion to buy and deploy 72 of the futuristic stealth fighter jets, in what is Australia's largest military acquisition.

Prime Minister Tony Abbott has previously credited the F-35, along with the Super Hornet and Growler electronic warfare aircraft, as giving Australia "a regional air combat edge".

"The F-35 will provide a major boost to the ADF's intelligence, surveillance and reconnaissance capabilities," he said.

"The acquisition of F-35 aircraft will bring significant benefits to Australia, including regional areas and [the] local defence industry."

While the F-35 has been billed as the smartest fighter jet on the planet, designed to strike enemies in the air and on the ground without being detected by radar, its development has been beset by delays and cost overruns.

The head of the JSF program, US Air Force Lieutenant-General Chris Bogdan, visited Australia earlier this year and declared the reliability and maintainability of the aircraft was not yet "good enough".

In late March, the US House Armed Services Committee was told the planes were not yet affordable to use.

The committee heard software problems could delay the fighter's production, and foreign buyer delays could see countries like Australia paying millions of dollars more per aircraft.

Defence Minister David Johnston responded to those reports, and reiterated the Government's commitment to the purchase.

"I'm not anticipating any drama, but should there be a major turnaround in cost, the option is available for us to leave the program," he said at the time.

"I don't want to do that because this aircraft is simply the best thing happening in air combat at the moment."