I have a Sony Cybershot it's a good camera but it's just the range of the camera that is the problem,
so I very close to aircraft and I don't travel as much as I use to . Then only planes I see are far away.
That is just a point and shoot close range type of camera, you might want to look at some DSLR cameras if you want to get into shooting airplanes. You can change the lens on the camera then and add zoom basically.
A DSLR is probably what you are looking for. Doesn't have to cost a fortune, but can if you want the best lenses and most advanced cameras. A Canon 400D or a Nikon D80 should be good enough, even a D40 could be a decent option if money is tight. You want a zoom lens of maybe 70-200 or even 300 if you are really far away from the aircraft. Browse around in different photo stores and forums and read reviews of lenses that seem to match your criteria and are in the right price range. When choosing a camera it's good to visit a photo store and ask to look at the equipment, then you can see what suits you. I use Nikon because it lwas comfortable in my hand than the Canon counterpart, but it's all individual preference.
There are other brands aswell, but Canon and Nikon are the biggest ones and there are lots of lenses, also second hand lenses avaliable.