I think there's a definite subcategory within the enthusiast's domain. I've always loved flying and aircraft in general, and having got into photography in the last three years, I've upped my exposure to the 'scene' rather alot.
One thing I have realised, is that the majority of spotters just aren't interested in aircraft, at all. It's all about the numbers, and I have to say I can't relate to it at all. Familiarity with registrations is a necessity if you're sharing your work at sites like airliners and jetphotos et al, but outside of that I know few photographers that really take an interest in that side of things.
For me it's all about sight, sound, and smell.
James