John Lackey   I will soon be trying to take photos of aircraft flying. I saw that you have a Flickr account and look at the EXIF data.
I have a few questions:  

Do you ever use a tripod to get some of you photos especially with the slow shutter speeds needed to capture the aircraft flying with the desired prop blur? I noticed a few of your shots were using 1/30 of a second shutter speed.

I had read in a blog post talking about back button focusing. I have since enabled that on my camera. Focusing is the biggest mystery to me. If you can explain what method of Auto Focus you use. That would be very helpful.