An F-22 Raptor shows heat as it screams away.
Air show photography tip: I regard the Canon EF 100-400 L USM Lens as the ideal Canon air show lens. On this day, I was using the Canon EF 400mm f/5.6 L Lens and the new-at-this-time Canon EF 70-200mm f/2.8 L IS II USM Lens with a 1.4x Extender in place - just to continuously evaluate them.
For single planes, it is hard to have too much focal length. But, if the lens becomes too large, it becomes hard to follow the fast action with - and probably requires a tripod. Using a tripod in the tight crowds also does not work well.
The other issue with long telephoto lenses relates to air clarity. This shot apears blurry from the heat generated by the f-22's engine, but examples this point.
Using the 400 worked great until the teams began flying out of formation at closer distances. A zoom lens works much better in these situations.
Photos from a fixed focal length lens will likely require more cropping in post processing than from a zoon lens.
The 70-200 + 1.4x were a good combination, but AF is degraded somewhat by the 1.4x and I had a couple of focus hunting issues. The 280mm resulting focal length on a 1.3x APS-H sensor DSLR was a bit short.
Image quality from any of these lenses combinations is great.