26 U.S. Code § 4043 - Surtax on fuel used in aircraft part of a fractional ownership program
The term “qualified fractional owner” means any fractional owner which has a minimum fractional ownership interest in at least one fractional program aircraft.
The term “dry-lease aircraft exchange” means an agreement, documented by the written program agreements, under which the fractional program aircraft are available, on an as needed basis without crew, to each fractional owner.
For purposes of subsection (a), a fractional program aircraft shall not be considered to be used for the transportation of a qualified fractional owner, or on account of such qualified fractional owner, when it is used for flight demonstration, maintenance, or crew training.
This section shall not apply to liquids used as a fuel in an aircraft after September 30, 2021.