There is no magic formula. I try to keep the aperture around f8 or so, while ensuring that the shutter speed does not get too slow. For airliners on approach I generally use aperture priority, but for fast-moving aircraft at airshows I use shutter priority for better control of the shutter speed. I am lucky to have a VR
stabilised zoom lens, which is useful in low-light conditions because I can use shutter speeds two or three stops slower than with a non-stabilised lens.
I try not not to use an ISO of higher than 100, to avoid grain in the shots.
When shooting light-coloured aircraft against a background of dark clouds, the camera will tend to meter for the clouds, meaning that the aircraft will be a bit over-exposed. I use exposure compensation of up to 1 stop to compensate for that - i.e. up to one stop less than the camera is telling me. Conversely, for dark aircraft aganst a light background I would over-expose by up to one stop.
Finally, I set the White Balance to "Cloudy".
Hope this makes some sense - and sorry I could not give a more definitive answer.