What Is a Kit-Built Aircraft and How Is It Registered?
March 7, 2026
Amateur-Built Aircraft: A Thriving Tradition
One of the most distinctive segments of the FAA Civil Aviation Registry is the experimental amateur-built category — aircraft constructed by their owners, often from kits, under an FAA regulatory framework that has existed since the 1940s. This is not a fringe activity. Tens of thousands of amateur-built aircraft are active in the registry, and new ones are registered every year. Experimental aviation is a deeply embedded part of American aviation culture.
The 51% Rule
The foundational requirement for an aircraft to qualify as amateur-built is the 51% rule: the builder must have constructed more than half of the aircraft themselves, for their own education and recreation. The aircraft cannot be professionally built and then sold as an amateur-built. The FAA verifies compliance through an inspection process before issuing the airworthiness certificate.
Kit Aircraft vs. Scratch-Built
Most amateur-built aircraft today are constructed from kits sold by companies like Van Aircraft (the RV series), Zenith Aircraft, Kitfox, Sonex, and many others. A kit typically includes pre-formed metal parts, fiberglass components, or pre-welded steel tubing, along with detailed instructions. The builder purchases the kit, spends hundreds to thousands of hours assembling it, and then seeks FAA certification.
Truly scratch-built aircraft — designed and built entirely from raw materials, often from published plans — are less common but still exist in the registry.
How Registration Works
After construction, the builder contacts the FAA and arranges for an inspection by a Designated Airworthiness Representative or an FAA inspector. If the aircraft passes, it receives a Special Airworthiness Certificate in the Experimental Category. The aircraft is then registered like any other aircraft, with a standard N-number, and appears in the FAA Civil Aviation Registry.
The registry record for an amateur-built aircraft will typically show the builder name as the manufacturer and list the kit company or the design name as the model.
Operating Limitations
Experimental amateur-built aircraft come with operating limitations that differ from type-certificated aircraft. They cannot be used for commercial passenger-carrying operations, and there are restrictions on flying over densely populated areas initially. These limitations are specific to each aircraft and are included in its airworthiness certificate documents.
To explore the experimental aircraft in the registry, use the aircraft search or browse by aircraft type.