Portrait of a Blue Angels F-18 Hornet.
Air show photography tip: For shooting single aircraft, a lens with a focal length of about 500-600mm full-frame-equivalent angle of view is about ideal. When multiple aircraft are flying, a zoom quickly becomes more useful.
Canon's EF 100-400mm L Lens is the best air show lens for most people. This focal length range will be short on a full frame body, but longer lenses become very heavy and are harder to follow the action with. Full frame users may also want to consider the Canon EF 400mm f/5.6 L Lens as it has less vignetting and you can plan on shooting at 400 most of the time anyway - and doing a lot of cropping.