It'll be a lot easier to tune an EFI on an aircraft, since you don't need a dyno for it to produce 100% power, or anywhere in between.
All you have to do is tie it down or hold the brakes and give it throttle.
The hard part is tuning for altitude...I'm not sure how comfortable you'd feel hooking up to the ECU and making changes to it while you're 8,000ft up.