259.3—Definitions.
Certificated air carrier means a U.S. air carrier that holds a certificate issued under 49 U.S.C. 41102 to operate passenger service or an exemption from 49 U.S.C. 41102.
Commuter air carrier means a U.S. air carrier as established by 14 CFR 298.3(b) that is authorized to carry passengers on at least five round trips per week on at least one route between two or more points according to a published flight schedule using small aircraft.
Large hub airport means an airport that accounts for at least 1.00 percent of the total enplanements in the United States.
Medium hub airport means an airport accounting for at least 0.25 percent but less than 1.00 percent of the total enplanements in the United States.
Small aircraft means any aircraft originally designed to have a maximum passenger capacity of 60 or fewer seats or a maximum payload capacity of 18,000 pounds or less.
Tarmac delay means the holding of an aircraft on the ground either before taking off or after landing with no opportunity for its passengers to deplane.