There are a number of quite good cameras that fit your requirements. You want what is termed a "megazoom" category point and shoot with a zoom that will reach at least 450mm expressed in old 35mm-film camera terms. In practical terms that means one with at "10x optical zoom" or higher. It will also have image stablization.
The one that I have is a Sony DSC-H2, which is thoroughly obsolete and available very cheaply now. The current model is the DSC-H10, I think, or maybe they are up to H11 now. Anyway, they've superseded my model at least 3 times over. But I am not sure the latest ones are really much better.
If you want to see what kind of pictures it takes, all of the shots in this gallery of the 2007 Chino show were taken with this camera:
http://rides.webshots.com/album/469071301RomNKK
Every major manufacturer makes these. I think that the Panasonic ones may be a little better than my Sony. The others are all about equally good.
The good news about these cameras is that they are wonderfully compact, have long reach, and the image stablization makes it easy to get good pictures of moving targets. I find that the best technique for using them at airshows is to turn off all the auto features, set the exposure manually, and lock the focus at infinity. This minimizes shutter lag (the time between when you push the button and when it gets around to actually taking the picture) almost to DSLR levels. The bad news relates to image quality. They have tiny sensors, which creates a lot of noise in the image and makes it pointless to go beyond 6 or 8 megapixels. They mostly save only to JPG files, which adds more noise (I think the latest ones have a RAW option which is the one thing that may tempt me to upgrade). And the lenses, which have to cope with these absurd zoom ranges, perform poorly, with a lot of chromatic aberration (color fringing). Some of these problems can be reduced afterwards with photoshop, but you're never going to get DSLR or 35mm-film quality out of them. But if web sized shots like the ones in my gallery would be good enough for you, these may be just the ticket. I carry mine with me whenever I'm going to be near an airport, and use it at airshows that I go to during business trips when I don't have room for my industrial grade photo gear. HTH.
August