Ultralight Aircraft in the United States are covered by the Code of Federal Regulations Title 14 (Federal Aviation Regulations) Part 103 or 14 CFR Part 103, which defines an "ultralight" as a vehicle that:
* Has only one seat.
* Is used only for recreational or sport flying.
* Does not have a U.S. or foreign airworthiness certificate.
* If unpowered, weighs less than 155 lbs.
* If powered:
- Weighs less than 254 lbs empty weight.
- Has a maximum fuel capacity of 5 U.S. gallons.
- Has a top speed of 55 knots (63 mph) calibrated airspeed at full power in level flight.
- Has a power-off stall speed of 24 knots (28 mph) calibrated airspeed or less.
Certification:
* Ultralight vehicles and their component parts and equipment are not required to meet the airworthiness certification standards specified for aircraft or to have certificates of airworthiness.
* Ultralight vehicles are not required to be registered or to have registration markings.
* Operators of ultralight vehicles are not required to meet any aeronautical knowledge, age, or experience requirements or to have airman or medical certificates.
Operations:
* Ultralight vehicles cannot be flown except between the hours of sunrise and sunset.
* Ultralight vehicles may be operated during the twilight periods (30 minutes before official sunrise and 30 minutes after official sunset) or, in Alaska, during the period of civil twilight as defined in the Air Almanac, if:
- The vehicle has an operating anti-collision light visible for at least 3 statute miles.
- The flight is only in uncontrolled airspace.
* Ultralight vehicles cannot be flown over any congested area of a city, town, or settlement, or over any open air assembly of persons.
* Weight allowances can be made for amphibious landing gear, and ballistic parachute systems.
In the United States, while no license or training is required to legally fly ultralights, training is highly advisable and required for vehicle use at most airports.