From EAA's web site:
EAA, the Experimental Aircraft Association, is a growing and diverse organization of members with a wide range of aviation interests and backgrounds. EAA was founded in 1953 by a group of individuals in Milwaukee, Wisconsin, who were interested in building their own airplanes. Through the decades, the organization expanded its mission to include antiques, classics, warbirds, aerobatic aircraft, ultralights, helicopters and contemporary manufactured aircraft.
More importantly, the organization focused on people, offering the opportunity to make new aviation friends and form relationships while encouraging the sharing of information, stories and enthusiasm. The focus of EAA is communication, through our publications, Chapter network, websites, AirVenture and numerous other programs. There is literally something for everyone.
You don't have to be a pilot or aircraft owner to be a member of EAA. You can find different ways to fulfill your aviation interest, whether it's participating in EAA's Young Eagles (with a goal of giving one million kids an airplane ride) or visiting the world's premier aviation event . . . EAA AirVenture Oshkosh.
For the long-time aviation enthusiast and pilot, EAA has programs and activities that allow you to meet others with the same interests. If you have dreamed of flying, but didn't realize you could participate, I invite you to join EAA. Learn more about what we have to offer. More importantly, meet others just like you.
Today, aviation is competing with other recreational activities. Therefore, we want you to feel welcome. We must share the opportunities available and invite you to the multitude of EAA events that showcase aviation at its best. Whether you are interested in building, buying or owning an airplane; seeing the world's greatest air show performers; meeting aviation personalities; or just enjoy being around airplanes . . . EAA is the place for you.
Another cool thing about EAA is that they're a member of the Ford Parter Recognition program. By joining EAA, you become X-Plan eligible. The only caveat is that you have to be a member for one year before you can use the X-Plan.