Generally speaking, you should probably get an SLR, plus a lens that is at least 300mm. 200mm is also good, except you can't be too far away from the action and shots of cruising aircraft are poor. The "prosumer" type cameras that don't have interchangeable lenses vary greatly, but some have the magnification that you need.
All these sites are great for both info and reviews.
Here is a great site to purchase used camera products. If you find that the D60 and Canon EF 75-300mm III USM lens aren't what you want I know that this site will offer a great selection for any type of camera. I have bought a lens from here and it was a great price and as promised it was in great shape. My friend just got a D60 from this site and again as promised it was in great shape and he paid a pretty good price.