After years of delays, technical problems and massive cost overruns, the most expensive warplane in history is finally about to make its international public flying debut.

Key points: The F-35 will finally debut on July 8-10 after being pulled from Farnborough in 2014

The F-35 will finally debut on July 8-10 after being pulled from Farnborough in 2014 Australia has orders in for 72 to be delivered by 2020 at a cost of $17 billion

Australia has orders in for 72 to be delivered by 2020 at a cost of $17 billion Production has ramped-up after the Pentagon in February identified technical glitches

The F-35 stealth fighter is set to roar through the skies over England next month, first at the Royal International Air Tattoo, then at the Farnborough International Airshow.

The Pentagon hopes the displays will convince program partners and prospective buyers that the plane's many problems may at last be behind it.

First envisioned in the early 1990s, the F-35 will eventually form the backbone of America's and Australia's fighter fleet.

But the program has come with a ballooning price tag — now at almost $540 billion — for the nearly 2,500 planes that will be produced in the coming decades.

Lieutenant General Chris Bogdan, who is overseeing the program for the Pentagon, said most of the work developing the F-35 would be done by 2018.

The plane has actually already gone into service. A year ago, the US Marine Corps declared a batch of pared-down F-35Bs as operational, marking a major milestone.

The F-35 comes in three designs, with the F-35B capable of landing vertically and making short takeoffs. The F-35C is for use on aircraft carriers.

Five planes — three F-35B and two F-35As — are set to fly at the Royal International Air Tattoo on July 8-10, and three F-35Bs will fly at Farnborough the following week.

Two Joint Strike Fighter F-35A aircraft in flight. ( Supplied: Defence )

Hopes that jinx has lifted

It was supposed to have flown at Farnborough, one of the world's top airshows, back in 2014, but the entire F-35 fleet was grounded when a plane's engine caught fire while training in the United States.

That incident was another in a string of blows for the F-35, which has suffered so many setbacks that at times has seemed jinxed.

Australia's F-35 Joint Strike Fighters In the 2013 Defence White Paper, the Government said it would bring in the fifth-generation F-35A Joint Strike Fighter aircraft, with three operational squadrons planned to enter service from 2020, to replace its Hornets. The Government said the fighter, built by Lockheed-Martin in the US, was chosen for its "stealth" technology, advanced sensors and weapons required to maintain an air combat advantage into the future. In October, the Government confirmed it would push ahead with its $17 billion purchase of 72 F-35 Joint Strike Fighters. Read more: The big ticket items on the ADF's shopping list

A Pentagon report in February said the F-35A model remained dogged by problems, including software bugs and technical glitches. And issues with the eject system meant it could potentially kill pilots below a certain weight.

But industry watchers and Pentagon officials now say Lockheed Martin's Joint Strike Fighter, as it is also known, is progressing.

Production levels are ramping-up, and Lieutenant General Bogdan said 53 aircraft should be delivered this year, compared to 45 in 2015. About 155 F-35s have been produced in all.

The eight other countries participating in the F-35 program are starting to get their planes, including the Netherlands which this year took delivery of two F-35As in Leeuwarden.

"Technically, it has definitely seen the worst," said air industry expert Richard Aboulafia, vice president of analysis at the Teal Group.

Retired lieutenant general David Deptula, dean of the Mitchell Institute of Aerospace Power Studies, said pilots who have flown the F-35 acknowledge challenges but say the F-35 is potentially an "extraordinarily valuable addition to the nations that will be operating" it.

According to Lieutenant General Bogdan, the cost of each F-35A is expected to drop to less than $114 million by 2019.

AFP