The moment British F-35B aircraft landed at their home base this year.
Aircraft will take off from bases around the country, and the number involved has almost doubled this year.
Air Commodore Jez Attridge said, "The first point of an air force is to be able to defend the country so you have to recognise the threats out there." He added:
"We can see the environment is changing, we can see the challenge that Russia is giving to the international rules-based order so we are the insurance policy."
He went on to say, " We are recognising that through the scenario that we've got, the non-permissive environment, our ability to operate with our allies, the French and the Americans, is paramount. It really is a case of us staying ready so that we can be used if we need to."
Commodore Attridge described the inclusion of the two F-35s as a "huge milestone" which "really shows the progression that Lightning Force is making".
Wing Commander John Butcher, the officer commanding 617 Squadron, said:
"This particular exercise is different than any ones that we've done previously because of the threats that are out there."
He added: "It's the first time we've done a peer exercise and that we've worked alongside French and US partners."
He said "things are progressing well" towards declaring initial operating capability for the F-35s before December 31.
F-35B aircraft have been involved in flight trials with aircraft carrier HMS Queen Elizabeth off the coast of the United States, with American F-35B aircraft flown by British pilots the first to land and take off from the warship.