I've been following this thread for some time trying to figure out what kind of textures you are really looking for. I mean, F-22 is not some "fun" plane with a lot of cool stuff painted on it. It is basically a piece of brushed metal with some signs/text here and there.

I googled "F-22" and found tons of images that you could use as reference. Here is just a couple that I thought were a good general reference:

https://www.fas.org/man/dod-101/sys/ac/f-22-991769b.jpg

https://www.fas.org/man/dod-101/sys/a...-0000l-001.jpg

https://www.wallpaper.net.au/wallpape...201024x768.jpg

https://www.milnet.com/pentagon/usaf/f22-paint.jpg

https://www.warchina.com/newimg/f22.jpg

https://www.usu.edu/afrotc/images/f22%202.jpg

https://www.personal.psu.edu/users/c/r/crs247/f-22.jpg

What you should do is make sure that your model is UV mapped in a reasonable way, take a snapshot of the UVs and start playing in PS. I think there was already enough people who pointed out that PS is really an essential tool for texturing.

However, your model is never going to look "real" if you just apply a texture to it. The surface has to react properly to light. First create a shader that will behave like a brushed metal (you can google "brushed metal shader" and you will find a lot of tutorials/shaders that you can use). If you really want it to look real, find out what metal it is made of and create a shader that will be as close as possible to it.

From the images I noticed that it has almost no highlights (or rather VERY soft ones) and the surface diffuses light a lot.

I would start with a blinn shader, give it a grayish-blueish color, make the highlights very soft, and go from there. Once you have your basic shader set up, apply the texture and start tweaking from there.

The resolution of the texture really depends on how close you'll get to your model. If all you want to do are flybys don't worry about a very detailed texture...

Good luck