The Pentagon says its F35 Joint Strike Fighter fleet remains grounded days after an engine fire at a US Air Base.
The Lightning 2 will be the main air asset on Britain's new aircraft carrier, HMS Queen Elizabeth. It will also replace the RAF Tornado and the Harrier, which was scrapped under defence cuts.
But just days after the official carrier naming ceremony, hopes of seeing the fighter at the Royal International Air Tattoo this Friday remain in doubt.