So, I've seen the Cessna flying on Youtube with sound effects, but one thing that'll make a huge difference in any game is music.
I just wanted to mention that and point to some amazing and freely available tracks I've found.
This would make a great main menu theme:
(just imagine a sunrise from orbit over a crescent Earth to this!)
(Set the camera at 150 or 350 km altitude, and have it go around the Earth at 7,800 m/s for perfect orbital view)
Some exploration music:
It looks like all he'll want (the composer) is credit if asked for the music.