California Code, Public Utilities Code - PUC § 21012

“Aircraft” means any manned contrivance used or designed for navigation of, or flight in, the air requiring certification and registration as prescribed by federal statute or regulation. Notwithstanding the foregoing provisions of this section, manned lighter-than-air balloons and ultralight vehicles as defined in the regulations of the Federal Aviation Administration (14 C.F.R. Part 103), whether or not certificated by the Federal Aviation Administration, shall not be considered to be aircraft for purposes of this part.