Lots of interesting points here. What about a switch on your remote to simulate doppler effect, so when the plane is about to pass you (and the crowd around you), you hit the switch to go from a higher to lower pitch of the sound... ? I dont know... just mumbeling on here...

If you are using a 30+ cells motor setup, it should be possible to borrow some juice from that so you need a audio-simulator/amplifier box with a super efficient speaker of some sort connected...