Airway Distance: The actual (as opposed to straight line) distance flown by the aircraft between two points, after deviations required by air traffic control and navigation along established routes. The difference between this and straight-line distance varies throughout the country.

Block Rates: A lower "contract rate" for scheduling significant amounts of charter time, in advance on a pre-arranged agreement.

Block Speed: The average speed over a specific distance "block-to block,” or door-to-door with respect to the airport gate.

Charter Operator: A company or individual that holds aircraft charter certificate and provides charter services to retail and wholesale customers.

Duty Time: That portion of the day when a crew member is on duty in any capacity (not just in the air). Check it out before planning a trip too tight to the limit as many charter operators have strict rules.

Empty Leg: Also known as "one-way availability.” Since charter trips typically charge for the round trip travel of the aircraft, empty legs can often represent relative bargains. These are usually posted as available for travel between two airports during a certain time period.

Fleet Manager: A commercial aviation entity developed to subcontract the maintenance and operation of corporate aircraft, which are often chartered out to the public.

Flight Time: The portion of the trip actually spent in the air. For billing purposes this definition is generally strict and only applies from moment of lift-off to moment of touch-down.

General Aviation: Aviation; other than military or commercial scheduled operations. Commercial unscheduled operations, corporate flight operations and private aviation are the most conspicuous members of this group. Most major metropolitan airports tend to have a separate "general aviation" terminal, where a chartered flight is likely to depart or arrive

Positioning Time: Estimated time for an aircraft to travel to the trip departure position.