If you are concerned about
(a) portability and stuffing the camera in the navbag, a small compact - but usually too wide to be of great use in long range shooting.
(b) flexibility, you need a good zoom lens. I use a Canon D10 and swear by it. Changing lenses gives you all the flexibility you need and, for cockpit use, a decent zoom is all you need. However, there are a half dozen similar capability cameras in the marketplace - take your pick.
As always, most things are a compromise in decision making.