Now these will be ideas based upon what i have thought of through my whole time playing SimplePlanes... so lets get to it!:

Squadrons:
Sort of like a clan, but more based upon air force terminology.

New parts:
Laser-guided bombs, electronic warfare kit, triangular shaped malleable pieces, more cockpit styles, arrestor hook, modifiable landing gear, a single-wheel front landing gear, landing gear that retracts like it did on the P-40, malleable intakes, thrust vectoring engines, a 30mm and 50mm cannon that takes 3-5 seconds to reload a powerful shot (Adding more if i think of them).

Extras:
Carriers have arrestor cables and working elevators with working spawn locations wherever on the carrier, sonic booms, new GUI in the cockpit (seeing a joystick, throttles, rudder pedals, buttons, screens, and we can change it to what ever era we want from the 1900s to the 1930s-40s to the 50s, 60s, 70s, etc., and a screen interface.), more land masses (small islands and such, possibly with destructable buildings or hostile enemies that intercept you), having more military missions, such as recon, electronic warfare, dogfights, drag races, normal races, and historically accurate battle scenarios; and now the final thing: a small multiplayer platform that could just be another app that you can transfer planes to and then fly them around online. We'd need more mods to take care of each server (possibly 3-6 servers in total) and just start out small guys... or just make SP2 with lots of more cool ideas i didnt think about while writing this!

P.s. my idea for online is for the purpose of hanging out with friends, engaging in friendly dogfights, and just flying around with the best of the best. Now nobody is saying its going to be absolutley peaceful, since there are trollers and hackers out there who would want to mess with people. Thats what we have Mods for! They are doing the best they can to help all of us out, and we thank them. Now for online, they wouldnt have to have their own airplane to fly around but could spectate all of the players, but without the player knowing. Anyway, thought id add on more in case of confusion. If you have anything to add to this or any questions for me, write in the comments and mention me!

Thx for reading! :)