Skids for the water and snow because I tried making the x2y sea dart and failed

Add more map customization like how we can download planes but also download maps
More landing gear options like how they contract into the fuselage how many points of rotation in them and more than one wheel in exact landing gear and have the tread options I know there were not that many planes with them but they are still fun to mess with if we had them

Wings with profiles can we please have actual air foils
Computers to help our planes fly if they are a little uncontrollable but basically trim on our planes so we can stabilize them
More fuselage change options like give us more areas of the fuselage block to change or have us be able to put our own changeable areas in the fuselage block

Afterburners as a option on all jet engines

Jet engines with changeable shapes
Give us engines inside fuselage blocks or engines we can shape like fuselage blocks are now
Contra rotating props and changeable nose cones give us the ability to add different sets of propeller blades on each propeller engine and the ability to add and change shape of nose cones

More cockpit options that flow smoothly with the body of planes give us something like the fuselage block except it's labeled as a cockpit and can fit inside other blocks

The ability in sandbox to allow us to have unlimited fuel or limited not just one

Ejector seats
Multiplayer
Parachutes
Stuff for helicopters
A bigger aircraft carrier
Bomb bays along with weapons and allow us to choose between options just add the basics .50cal a few more machine guns but cannons and bombs and include a nuke
And thrust vectoring engines