IANAL. I don’t even play one on TV. None of this is legal advice, and it only covers US regulations.
That said, FAA regulations on UAVs are pretty simple. UAVs are basically model aircraft, and the rules are:
- Below 400 feet
- Away from populated areas and full sized aircraft
- Not for commercial use
That last one is what’s giving everyone fits right now. As a private citizen, your options for flying UAVs commercially are limited. There is a process to get either an experimental aircraft certificate, or a wavier certificate. Experimental certificates are only granted for “R&D, market survey and crew training”, while waivers are usually only granted to government agencies. That includes local government agencies, so you could feasibly get a contract to survey land for a local town.
Some people have tried to skirt around things by taking aerial photographs on a hobbyist basis, but then claiming they charge a client for post-processing. I doubt the FAA or courts will agree with this reasoning; they’re really just hoping that they’re too small for the FAA to bother.
Short of government contracts, commercial use of UAVs is limited to selling them for now. The FAA is set to introduce new rules for commercial UAVs in 2015. Mark your calendars.