Well, I finally broke out my GameShark today to try this out! It's pretty neat. The AirWings shoot lasers (which take about 3/4 of a heart) and go down in flamey flames with a single hit from the boomerang. Also interesting is all of the flames that come from a downed AirWing - I figured walking into them would set Link "on fire"... They don't... Also, interesting enough, the AirWing seems to have it's own opening sequence - in that when you enter the area that the AirWing is in, the camera zooms in and focuses in on it for a few seconds...
It's a neat little thing. I wonder if there's some hidden level in the game where they're used... Perhaps they gaurd the Triforce.