Sorry if I missed it when I skimmed through these, but level autopilot is Ctrl+Shift+A. When you hit this the plane is gonna fly all over the place until it recovers to level flight in the direction you were headed, don't panic. I think Shift+A releases it. You can use this with the Ctrl+ Shift+E which will incrementally increase the speed up (2x,4x,8x, and 16x, I think) Ctrl+Shift+R will reverse the progression and Ctrl+X will cancel it.
If you get within 4nm's of an enemy the time warp and/or speed increase will automatically cancel, however I think you will have to manually turn off the Autopilot.
Just a note, don't use auto trim if you use the time warp, you will fall out of the sky, and if you use realistic engine controls, adjust your mixture before you warp or the engine will die if it comes out of warp at altitude.
You cant reload your machine guns, what you got is all you get. You can raise and lower the gun on the SE5 and the windshield on the N17 with Shift C,
Have Fun!
Beard