As for why they didn't film with F-35s: others have already mentioned that the F-35's single seat makes it impossible to put actors in the cockpit. Other issues are that the F-35 has a lower thrust-to-weight ratio than the F-18, so maneuvers wouldn't look quite as cool. Also the F-35 costs much more to run per hour of flight time, and I'm guessing there are issues with having so many civilians and cameras around the latest generation fighter plane. The chance of some classified information leaking is high.
When the one pilot asked, "Why not use F-35s for the mission?", I would have been fine with Jon Hamm looking directly at the camera and saying, "Because this movie is better with F-18s." The choice of fighter plane doesn't really affect the plot. If anything, using older planes improved the movie by raising the stakes when they went up against the Su-57s.
The scenario setup in the movie at least made this detail seem important. It's plausible to me that the F-18's higher thrust-to-weight ratio could've been critical in the canyon scene while navigating tight turns.
Of course, that could be ballocks and the main limitation would be pilot response times, etc. Still it feels plausible.
Though it made that scene where the characters are in an outdated and badly maintained F-14 slightly less believable. Like in the briefings, going up against the Su-57 with F-18 was seen as a dubious proposition, so with the F-14, the only way they'd survive was with their super-power of being main characters in a modern movie.
The f-35c is a single seater. The Navy isn't letting actors fly their jets. So the only choice is the super hornet.
The f-22 is an air force jet, not Navy. Top Gun is Navy. The f-22 is also single seat.
So now I wonder what they did in the movie.
in the movie, they bring up the mission requirements at low altitude render a certain tech of the new gen planes useless under the scenario because of its dependence on radar iirc
in real life the decision behind avoiding 5th is because most of the information about the planes are still highly classified, ie there is no full feature spec of 5th gen planes available, so no way united states military would let them film a plane
0: https://www.lockheedmartin.com/en-us/products/f-35-lightning...
While it ultimately produced a capable plane, the Joint Strike Fighter spent 15 years as the next generation, failed to meet several critical goals, and still hasn't entered full production.
Better to stick to concept planes (SR-72), the plane from the first movie (F-14) and another common carrier plane (F-18).
[0]: https://breakingdefense.com/2022/03/full-rate-production-for...
The fancy nextgen fighter programs, like most US "defense" spending, are noteworthy mainly for the staggering amounts of money we taxpayers shovel into arms dealers' pockets. Actually on second thought the enthusiasm with which we do that pocket-lining is also pretty impressive.
[1] https://www.navytimes.com/news/your-navy/2022/02/07/leaked-v...
[2] https://eurasiantimes.com/f-35c-stealth-fighter-jet-crashes-...
[3] https://www.f-16.net/aircraft-database/F-35/mishaps-and-acci...
[4] https://www.airforcetimes.com/news/your-air-force/2022/01/20...
[5] https://www.f-16.net/aircraft-database/F-22/mishaps-and-acci...
But as you know, the Eagles could have flown the ring to Mordor, but it would have been a boring story.
The whole plot hinges on that a hobbit was the most resilient against the corruption of the Ring. The Eagles were proud and powerful creatures. A ring-wraith Eagle would have been quite the setback to Gandalfs' plans.