This sector of aviation encompasses any lightweight vehicle designed to operate at very low speeds. In the United States the terms only refer to vehicles that meet the Federal Aviation Regulations in Part 103, “Ultralight Vehicles.” Ultralights are single-seat aircraft that can be either powered or unpowered.
Because ultralights don't travel at high speeds, they are often used just for sport and recreation. They usually cost much less than general aviaiton aircraft to purchase, and they require a minimal amount of training to get in the air.
The United States Ultralight Association (USUA) has been around since 1985, dedicated to the representation of ultralight pilots and enthusiasts. In its capacity as the sole authority in the U.S. to administer the microlight section of the FAI sporting code under the supervision of NAA, USUA sanctions a national competition program and an international flight achievement program.
U.S. Ultralight Association website: www.usua.org