Building an airplane is legal but heavily regulated, and the path depends on whether you want to fly it yourself or sell it

You can build an airplane in the United States without a factory license, but you cannot fly it or sell it without meeting specific Federal Aviation Administration (FAA) rules. The FAA distinguishes between amateur-built aircraft (also called homebuilt or experimental aircraft) that you construct yourself, and kit aircraft that you assemble from a manufacturer's parts. Both require an airworthiness certificate before flight, and both demand technical knowledge, significant time, and money. The route you take depends on your skills, budget, and whether you plan to fly the plane yourself or transfer it to someone else.

This guide explains what the FAA requires, how to choose between building from a kit or from plans, what workspace and tools you need, and how the inspection process works. It covers the real timeline and costs involved, and points you toward the communities and resources that make the difference between finishing and abandoning the project halfway through.

Key Takeaways

  • Amateur-built aircraft must be at least 51 percent constructed by the owner, and the FAA will inspect the build before issuing an airworthiness certificate.
  • You need a workshop space with tools, materials, and often specialized equipment; costs range widely depending on aircraft type and whether you buy a kit or source parts separately.
  • The FAA requires you to document your build process with photographs and records so inspectors can verify you did the work yourself.
  • After construction, you must pass an FAA inspection and obtain a special airworthiness certificate before you can legally fly the aircraft.
  • Kit manufacturers provide plans, materials, and support, while scratch-building from plans alone requires deeper engineering knowledge and takes significantly longer.

Understanding the FAA's 51 Percent Rule

The FAA defines an amateur-built aircraft as one where the builder (or a group of builders) constructs at least 51 percent of the aircraft. This means you cannot straightforward assemble a plane from prefabricated sections and call it homebuilt. The 51 percent rule applies to the actual construction work—welding, riveting, fabricating parts, assembling systems—not to the cost of materials or the complexity of what you build.

The FAA takes this seriously because they want to may support the builder understands the aircraft's structure and systems. When you request an airworthiness certificate, an FAA inspector will review your build logs, photographs, and records to confirm you did the work. If you cannot document your involvement, the FAA will not issue the certificate, and you cannot legally fly the plane. This is why keeping detailed records throughout construction is not optional—it is a requirement that determines whether your finished aircraft can ever leave the ground.

Choosing Between a Kit and Scratch-Building

A kit aircraft comes from a manufacturer with pre-cut parts, materials, plans, and often video or written instructions. Popular kit manufacturers include Vans Aircraft, Zenith Aircraft, and Kitfox. Kits reduce the engineering work because the design is already proven, and manufacturers provide support if you get stuck. Most kit builds take 1,000 to 3,000 hours of work, depending on the aircraft type and your experience. Kits cost between $20,000 and $60,000 for the materials alone, plus tools and engine.

Scratch-building means constructing an aircraft from published plans without a kit. You source your own materials, fabricate parts from raw stock, and do all the engineering verification yourself. Scratch-building requires deeper knowledge of aerodynamics, structures, and systems, and it typically takes 2,000 to 5,000 hours or more. It is cheaper in material costs but demands more skill and carries higher risk of design errors. Most first-time builders choose a kit because the design is already tested and the support is there when questions arise. The kit route also makes it easier to document your 51 percent of the work, since the manufacturer's instructions create a clear record of what you assembled versus what came pre-made.

Setting Up Your Workshop and Tools

You need a dedicated space to build—a garage, hangar, or workshop where you can leave work in progress and store materials safely. The space should be climate-controlled if possible, because temperature and humidity affect materials like wood, fabric, and composites. You will need basic hand tools (wrenches, screwdrivers, clamps, measuring tools), power tools (drill, angle grinder, saw), and specialized equipment depending on your aircraft type. A metal aircraft requires a rivet gun and bucking bar; a composite aircraft requires vacuum bagging equipment; a fabric aircraft requires a heat gun and fabric-stretching tools.

Tool costs vary widely. A basic hand-tool set runs $500 to $1,500. Power tools add another $1,000 to $3,000 if you do not already own them. Specialized equipment can add $2,000 to $10,000 or more. Many builders rent or borrow expensive tools, or join local experimental aircraft associations where members share equipment. The Experimental Aircraft Association (EAA) has chapters nationwide and offers workshops, tool libraries, and mentorship—joining is one of the smartest first steps you can take. Your local chapter can connect you with builders who have already solved the space and tool problems and may offer access to their facilities.

Documenting Your Build for FAA Inspection

From the first day of construction, photograph your work and keep written records. Take photos of major assembly steps, structural components before they are covered, and systems installation. Write down dates, hours worked, and what you did. The FAA inspector will want to see evidence that you personally built the aircraft, not that you hired someone or bought it mostly assembled. Without documentation, you cannot prove the 51 percent rule was met, and the FAA will deny your airworthiness certificate.

Create a build log—a straightforward notebook or digital file where you record each work session. Include the date, hours worked, what you built or assembled, and any challenges or decisions you made. Take photos from multiple angles, especially of joints, welds, rivets, and systems before they are enclosed. Store these records safely; you will need them when the FAA inspector visits. Some builders create a dedicated website or blog documenting their build, which serves as both a record and a way to share progress with the experimental aircraft community. This documentation also protects you if questions arise later about the aircraft's construction quality or your involvement in building it.

The FAA Inspection and Airworthiness Certificate Process

Once construction is complete, you contact your local FAA Flight Standards District Office (FSDO) to request an inspection. The FAA will assign an inspector who will examine the aircraft to verify it was built according to the plans, meets structural standards, and is safe to fly. This inspection is called a condition inspection, and it is thorough—the inspector will check welds, rivets, control systems, wiring, and documentation. Bring your build logs and photographs to show you did the work.

If the inspection passes, the FAA issues a special airworthiness certificate in the "experimental" category. This certificate allows you to fly the aircraft, but with restrictions: you cannot carry passengers for hire, you cannot use it for commercial purposes, and you must fly it within certain limits while you gather flight test data. The first 40 hours of flight are typically restricted to a designated test area. After you log those hours and the aircraft performs as expected, some restrictions may be lifted, but the experimental category remains. This means resale is possible, but the buyer must also be a pilot and will face the same restrictions.

Time, Cost, and Skills Required

Building an airplane is a multi-year project. A kit build typically takes 2 to 5 years of part-time work, assuming 10 to 20 hours per week. Scratch-building takes longer. Total costs vary enormously: a straightforward kit aircraft might cost $30,000 to $50,000 all-in (kit, engine, avionics, tools), while a more complex aircraft or one with advanced systems can exceed $100,000. These figures do not include hangar rental, insurance, fuel, or maintenance once the aircraft is flying.

You need mechanical aptitude, patience, and problem-solving skills. You do not need a pilot's license to build the aircraft, but you will need one to fly it. Many builders take flight training while building, so they are ready to fly when the aircraft is done. Joining the EAA and connecting with other builders in your area is invaluable—experienced builders can answer questions, help you avoid mistakes, and keep you motivated through the long build process. The community aspect matters as much as the technical knowledge; builders who stay connected to their local chapter are far more likely to finish than those who work in isolation.

Frequently Asked Questions

Do I need a pilot's license to build an airplane?

No, you can build without a license. However, you cannot legally fly the aircraft without a pilot's license and a medical certificate. Many builders obtain their license during construction so they are ready to fly when the aircraft is complete.

Can I sell an airplane I built?

Yes, but it retains the experimental airworthiness certificate, which means the buyer must also be a pilot and can only fly it under the same restrictions. The resale value is typically lower than a certified aircraft because of these limitations. Some buyers are specifically looking for experimental aircraft, so there is a market, but it is smaller than the market for standard aircraft.

What if I do not have a workshop space?

Many EAA chapters have shared workshop facilities or can connect you with other builders who have space. Some builders rent hangar space at small airports, which also puts them near the runway where they will eventually fly. This is more expensive but solves the space problem and puts you in the experimental aircraft community.

How much does an engine cost?

New aircraft engines range from $15,000 to $40,000 or more, depending on horsepower and type. Many builders buy used engines or rebuild engines, which can cost $8,000 to $20,000. Engine choice depends on the aircraft design and your budget.

What happens if I run out of time or money and do not finish?

An incomplete aircraft has no resale value as an aircraft, though you may recover some value by selling parts or the kit separately. This is why joining a builder community and setting realistic timelines matters—you are more likely to finish if you have support and do not overcommit financially.