14 C.F.R. § 259.3
Business days means Monday through Friday excluding Federal holidays in the United States.
Certificated air carrier means a U.S. carrier holding a certificate issued under 49 U.S.C. 41102 to conduct passenger service or holding an exemption to conduct passenger operations under 49 U.S.C. 41102 .
Commuter air carrier means a U.S. carrier that has been found fit under 49 U.S.C. 41738 and 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 as defined in 14 CFR 298.2 .
Covered carrier means a certificated carrier, a commuter carrier, or a foreign air carrier operating to, from or within the United States, conducting scheduled passenger service or public charter service with at least one aircraft having a designed seating capacity of 30 or more seats.
Foreign air carrier means a carrier that is not a citizen of the United States as defined in 49 U.S.C. 40102(a) that holds a foreign air carrier permit issued under 49 U.S.C. 41302 or an exemption issued under 49 U.S.C. 40109 authorizing direct foreign air transportation.
Large hub airport means an airport that accounts for at least 1.00 percent of the total enplanements in the United States.
Main aircraft door means the door used for boarding. In situations in which there are multiple doors that can be used for boarding, the last door closed is the main aircraft door.
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.
Non-hub airport means an airport with 10,000 or more annual enplanements but less than 0.05 percent of the country's annual passenger boardings.
Prompt refund means refunds made within 7 business days after the earliest date the refund was requested as set forth in 14 CFR 260.6(a)(2) as required by 14 CFR 374.3 for credit card purchases, and within 20 calendar days after the earliest date the refund was requested as set forth in 14 CFR 260.6(a)(2) for cash, check, debit card, or other forms of purchases.
Serious communicable disease means a communicable disease as defined in 42 CFR 70.1 that can cause serious health consequences (e.g., breathing problems, organ damage, neurological difficulties, death) and can be easily transmitted by casual contact in an aircraft cabin environment (i.e., easily spread to others in an aircraft cabin through general activities of passengers such as sitting next to someone, shaking hands, talking to someone, or touching communal surfaces). For example, the common cold is readily transmissible in an aircraft cabin environment but does not have severe health consequences. AIDS has serious health consequences but is not readily transmissible in an aircraft cabin environment. Both the common cold and AIDS would not be considered serious communicable diseases for purposes of this part. SARS is readily transmissible in an aircraft cabin environment and has severe health consequences. SARS would be considered a serious communicable disease for purposes of this part.
Small hub airport means an airport accounting for at least 0.05 percent but less than 0.25 percent of the total enplanements in the United States.
Suitable disembarkation point means a location at an airport where passengers can deplane from an aircraft.
Tarmac delay means the period of time when an aircraft is on the ground with passengers and the passengers have no opportunity to deplane.
14 C.F.R. §259.3