I own a 400mm f2.8 IS, and I love it. I shoot sports and it bring to almost any sporting event. But it it huge, heavy, and a pain in the butt or at least back. It does provide a unique look that is hard to duplicate.
I don't bring it when I hang with other non photographers. They think it's cool for about 2 minutes and then your are just slowing them down. I have a 300mm f4 IS for that.
Anyway, I see the choice to go big or small white as 2 sides of the same coin. Both have their advantages and disadvantages. The photo below is not from an airshow, but a C-130 doing touch and goes. Spotted when I was on the way home from a surf contest.REX50056 3eh
, on Flickr