The F-22 is going to be replacing the F-15 eventually. Air Superiority.

The F-35 is going to be replacing a wide array of planes, the F-16, F/A-18 and the A-10 (lol). I might be forgetting a few other planes. Multi-Role.

Now I'm not going to give you the long story because nobody has time for that. But the F-22 is expensive as hell. So expensive in fact, that the Air Force had originally planned to buy around 600 F-22s but purchased under 200 because of costs. They were also banned from being exported to other countries which did not help lower the price of the F-22. The F-35 is meant to be a more affordable option, as stupid as that might sound with the current pricing. The Air Force plans to buy over 1700+ F-35s (which perhaps is good for those like me trying to earn a pilot slot) over the next few years, as well as other countries such as Japan, South Korea, U.K., Austrailia, etc. which will drive down the costs over time. For example, the Air Force F-35A costs around $114 million, but that's currently low production costs. As more orders are filled, the price of the plane will decrease to around $85 million. This may sound expensive (and it is) but keep in mind these planes are replacing a wide array of aging aircraft. Now what about buying parts for these planes? The fact that this plane will be used in three of our branches and many more throughout the world will help keep costs down immensely. While it has been criticized for only having one engine, that helps keep costs down and ease of maintenance. And AFAIK, it is the only modern plane to have built in night vision, which is pretty useful when you think about it. No upgrades required there. And lastly, while the cost of these planes is extremely expensive so far, if these planes have a service life of say 50 years, it'll have saved major money. All these planes having the same design means using the same parts (not referring to things like the Marines' STOVL) saves money across the board. Having one engine means spending less on maintenance than if it had two engines. This plane is meant to save money in the long run. It's had a terrible start believe me, but wait until 2030 or so. Everyone used to bash the F-22, and now everyone loves it (even though it's been plagued with terrible problems, but the media doesn't care anymore since we're not buying anymore F-22s). The same will happen to the F-35 once they get all the kinks fixed. The F-35 is actually a pretty good fighter jet that performs well for what it needs to do. People just need to stop the F-35 hate circlejerk, because when I ask why they don't like it, it's because it's either ugly, expensive (despite me explaining how the costs will decrease over time and all the aircraft it's replacing, whereas the F-22 that they love is even more expensive but that's okay because it's cool) , and it "sucks." If you are knowledgeable about the plane and it's capabilities and don't like it, that's fine because not everyone is going to like the same thing. But to hate the F-35 because it "sucks" compared to the F-22 when they perform two completely different missions is a shame. Not bashing you, just making a reference because anytime I ever hear the F-35 mentioned it's just getting bashed.

Anyway, nearly every plane has been plagued with problems from the start, and some still carry those same problems with them years or decades later. Example, THE American plane of WWII, the P-51, was riddled with problems until they replaced the previous engine with a Rolls Royce Merlin engine. The F-22 still has some pretty serious problems, including software glitches, pilots passing out from lack of oxygen, toxic glue, the terrible "Raptor Cough", etc. Nearly every plane in production has had problems one way or another. You don't just build a perfect plane just like that. The F-35 is a fine plane, and is having problems just like nearly every other plane out there and it takes a while to fix the problems.

By the way, I am no expert in planes. I just have a passion for them and hope to earn a pilot slot next year. If I made a mistake or if there's anything that doesn't sound right, let me know. I'm always up for discussion when it comes to this type of stuff.