For which type of aircraft can 2-inch letters be used for registration?

The use of 2-inch letters for registration numbers is specifically allowed for certain types of aircraft, including spherical balloons and powered parachutes. Regulations set forth by the FAA state that the size of registration markings can vary based on the type of aircraft, and for these lighter-than-air craft and certain ultralight vehicles, the smaller letter size is permissible. This provision is designed to accommodate the unique characteristics and visibility requirements of different aircraft types.

In contrast, other aircraft categories such as fixed-wing aircraft typically require larger registration markings to ensure readability and compliance with safety regulations. Additionally, seaplanes are classified under similar requirements as fixed-wing aircraft regarding registration markings. Thus, the legislation recognizes the unique needs of spherical balloons and powered parachutes, leading to the acceptance of the smaller 2-inch letter size for these specific aircraft types.