Lockheed Martin officials say they remain hopeful that they can get the F-35 to display at air shows in the U.K. despite the ongoing grounding of the combat aircraft.

With only an F-35 mock-up as a backdrop, company officials began media briefings on the Lightning II as other military aircraft began arriving at the Royal International Air Tattoo at RAF Fairford on July 9, but were unable to give a firm answer on when or even if the aircraft will make their transatlantic trip and arrive in time for their planned international debut display at Fairford on July 11, followed by the Farnborough air show the week after.

The groundings were prompted by a fire that broke out on June 23 on an F-35A preparing for takeoff of Eglin AFB, Florida. Initially, commanders at each F-35 main operating base ordered a safety hold, but this was over-ridden by a Pentagon directive on July 3 that grounded the 100-strong fleet of aircraft.

Engineers worked through the U.S. Independence Day weekend to discover what caused the June 23 incident.

Company officials are hoping clearances to fly might be granted on an individual aircraft basis, allowing the F-35s selected by the U.S. Marine Corps and the U.K. to make the journey. Lorraine Martin, general manager for the F-35 program, hinted that if the aircraft weren’t cleared in time to attend the show at Fairford, they would still aim to attend Farnborough.

Martin, who was was unable to give detail on the progress of the investigation told reporters: "We have our brightest minds at work on this and supporting the investigation. We are also working closely with [F135 engine maker] Pratt & Whitney.

"I have full confidence that before the end of the two shows, we will have a F-35 here in the U.K. That is the intention of the U.S. and U.K. governments," she said. "They want the aircraft to be here."

The Marine Corps originally planned to arrive on June 29 and had pre-positioned three of its Yuma, Arizona-based F-35Bs at NAS Patuxent River, Maryland, to make the crossing, but that date has progressively been pushed back because of the grounding. They were due to be joined by the third British aircraft, BK-3 that had been due to fly up from Eglin AFB. But BK-3 was still at Eglin on Tuesday.