Travelocity doesn't pay American Airlines to get their data. They and virtually every other travel agency online and off uses a program called Sabre. That searches through all of the various airlines, hotels and car rentals and pulls up results based on their input.
http://www.sabretravelnetwork.com/
You don't have to be licensed per say but in order to get the software you have to have a membership number for the organization that coordinates the travel professionals. I can't remember off hand what the name of that association is but it's like the National Association of Travel Professionals or some other crap like that.
If you become an affiliate of airlines, hotels, car rental places, etc. you make a very small commission. Airlines only give like $2 or $3 per ticket sold. Not real great.