Beware of the digital camera...unless you have lots of money to spend. For the most part, the average digital camera cannot compete with standard film (in terms of resolution). However, there are some professional digi-cams that can shoot really nice images.
FYI, I shoot with a digital camera (Fuji MX-2900). It's not quite a professional model, but it still takes a decent picture at high resolution (1800x1200). The best part is that it offers MANY MANY options (shutter speed, white balance settings, etc.). As long as I'm close to the action, I can get really good shots. Which brings up an important point - most digital cameras don't offer a quality zoom...something which is crucial for something like aviation photography. Check out some of my latest images (October and later of this year) on this site to see what a digital camera is capable of. As you will see, the resolution isn't quite up to 35mm standards.
So...if you want to go digital, get a model with HIGH resolution that offers LOTS of options. In a nutshell, you get what you pay for.
San Diego, CA