I agree with what others are saying here and the comments section. The three free aircraft seems too high. With only 5 to fly at the moment any new players enticed by the free aircraft are unlikely to stick around for too long.
I still feel the Kickstarter required addons to allow people to customise their pledges to how they wanted them. Examples of which are in the text document I sent via Kickstarter. Edited version here https://www.dropbox.com/s/kprpuvvppisk1p3/Kickstarter%20Help.odt
Most importantly Keep funding open after Kickstarter to help reach the stretch goals. Kickstarters (over the current $40) will get any of the goals hit through additional funding. The additional funding should have higher pricing (still lower than final) to reward those who have backed early on in this Kickstarter. As you hit the steach goals the reward prices should raise to reflect the additional value.
Doing this would mean current backers get best value and it's profitable for them to get as many people as they can to add to the funds.
Also keeps the people informed with video updates, live streams, WIP screen shots, polls.