The Manning-led effort began in Atlanta where the airplane was housed early Saturday, with about 20 employee-volunteers from AirTran Airways, flying a mostly empty aircraft to Indianapolis, Indiana, to pick up the supplies.

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Getting the scheduling wrong imposes a heavy cost: flying half-empty planes or leasing extra aircraft is an expensive business.

ECONOMIST: Algorithms

Without spare pilots or airplanes in New York, the airline decided to fly passengers to Atlanta to swap aircraft and crew rather than fly an empty plane to New York.

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More than 70% of the time the aircraft fly with one or two people as passengers and they often fly empty after dropping someone off or picking someone up.

ECONOMIST: Bush fire

Also, the more your aircraft is used, typically the less it is worth On the other hand, there are some potential tax benefits from chartering your aircraft, and allowing it to be chartered could be beneficial if you are filling what would normally be empty leg flights.

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