Aircraft are difficult to record well as they tend to move quickly and not always in a way that works well with mic placement. I tend to leave around 18 - 20dB headroom (yes, a bit generous). If I'm expecting anything to fly close and up to 25 db if there's a prospect of anything with a jet engine. With aircraft and places I know well I usually shift around mic placement to get different recording dynamics. For places I don't know or new aircraft I'll make a call first then leave it that way and see what happens. I guess this is quite like how people that record birdsong will work. My usual kit comprises of a Rode NT4 or Audio-Technica 822 into a Fostex FR2-LE. Some of the older recordings use HI-MD Sony Minidisc.
For more information about these recordings or to request a high quality recording for your own use please contact me via email@example.com.
I can also record your aircraft or airshow. Please contact me for more information.