There are several types of photography that are very similar to real estate photography and depending on your geographic location can do one of these types of photography as an extension to a real estate photography business:
Lee Jinks in McAllen, TX who has an extensive background in aviation told me about his experiences breaking into corporate aircraft photography:
About two years ago my friend, a Lear pilot, asked if I would shoot a Cessna Citation that was in the same hangar as his plane. I looked at the job as an opportunity to try something new and experiment. It was fun, and I think I got some pretty nice photos. I hadn't planned on charging him because it was more of a favor, but the pilot of the Citation gave me some cash for my efforts.
I then began to think that this would be something fun to do if I could get my foot in the door. Well, this weekend my friend had an aircraft broker call me to shoot his Lear. The broker was impressed with my photos and I think he plans to use me as his go to photographer for the southern United States.
What's nice is that most of the techniques are quite similar to those I use for real estate. I found that there where two situations where I could not shoot level and this was hard to do after shooting real estate for so long. In order to get out of the photo from the mirror and capture the seat and sink of the bathroom, I had to shoot at a weird angle. Additionally, the cockpit and panel had to be shot at an extreme down angle. Now that I see the photo, it's much like many panel shots I've seen. I can see some improvements I need to make, but this was my first real jet shoot and I am generally pleased with the photos.
The down side is that these corporate jets are quite small and once you get your tripod and lights set up, there isn't much room to maneuver. Plus, they don't cool down the aircraft, so the environment is like working in your attic during summer. It's not for everyone, but for those who love aircraft and like traveling, it might be fun.
Here is more of Lee's shoot: