I liked the version very much. 21:9 support is great!
My Specs are:
i7 4770k @ 4.5 GHz, GTX 1080 Strix Advanced Edition
2560x1080 ~67 FPS //The game doesnt seem to make any difference between looking in the sky and being in combat
3440x1440 ~47 FPS //Seems to be scaling well but at higher resolutions AA is not needed ;)
I think the engine is handling just fine!
I would suggest some things: (some things are pretty obvious but meantioning them wont hurt)
1. Please introduce joystick support + any key mapping. (even for an arcade style game joystick support is just taking it to a whole new level)
2. Either I didnt found it or you need to give the player an option for deploying Flares.(eventhough the AI has them) I think it would be a good idea to have different kinds of countermeasures against different types of missiles (like ECM or something).
3. If you are going for something like HAWX or ace combat variety is very important, get as many different planes and locations as you can possibly get in there.
4. Don't be afraid to make the game a bit harder and try to introduce some different difficulty options.
5. A "safe mode off" feature where you have better turn ratios but less precision would be amazing.
6. Yet again correct me if I am wrong but selected enemies should be marked on the map/radar.
7. An advanced graphics options menu would be very important since depending on hardware some features just eat performance (e.g. AA at high resolutions).
8. Weaponary types should be explaned in the menu.
9. The menu should be compatible with gamepad.
If I come up with something I let you know (if you want my advice ;D).
Keep up the great work!