Aircraft photography ..... quick query on appeture

I have only done one airshow before, but im off to RAF Cosford airshow on sunday and i wondered what the best appeture is for planes in flight to ensure best sharp results. I will be shooting with my new 1dx, 70-200 f2.8 and my 100-400.
The weateher is meant to be good and sunny so the light should be good enough to open the appeture up.
Thanks very much
Andy

You're going to want to be more concerned with shutter speed than aperture.

Generally, 1/250 and slower for props and take the aperture you get. On extremely sunny days, you might consider two or three stops of ND simply to avoid spending the day at f/16-f/22.

If you want to work jets off of aperture priority, you can. I prefer to shoot them 1/2 stop under wide open just to get a little bit away from wide open.

Thanks Jay. I had read a lot re shutter speed etc, but no one was mentioning appeture...... so I ended up looking at your crosswinds website as you post exif data and from that worked it out.
The one thing with the 1dx Is you dont get noise until iso 12500, so I have the ability to play a bit with very fast speed plus appeture. I spent most of today over 1/1000 up to 1/5000 for the jets and tried getting prop movement on the prop planes between 1/60 and 1/250.

Thanks for having such a useful website. Helped me prep for today.
Andy

Glad to be of help...