Engines of Our Ingenuity

No. 1979:
AIRPLANE RESERVATIONS

by John H. Lienhard

Today, guest scientist Andrew Boyd buys plane tickets. The University of Houston presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

The 1940s saw the airline industry at wits end. As flight networks grew, it was becoming impossible to keep track of passenger reservations. Handwritten three by five index cards were complemented by huge rooms filled with chalkboards showing what flights had seats available. But those rooms were becoming unmanageable. Some reservation agents kept binoculars near their phones. That way they could avoid long walks to faraway chalkboards, in search of available seats.

Gumball machine Author Thomas Petzinger tells how American Airlines developed an ingenious rudimentary mechanical solution. They set up cylinders in a room, one for each flight. Marbles in the cylinder represented the number of seats on the flight. The cylinders looked like candy dispensers. When the reservation agent made a booking, he'd push a button that caused a trap door on the appropriate cylinder to open. A marble would fall out, and it recorded the booking.

In 1953, the integrated circuit had yet to be invented. Yet, it was during this year that a chance meeting between an IBM representative and the president of American Airlines would lead to the birth of the first computerized reservation system. Other major carriers soon followed in spite of tremendous cost and years of effort. TWA spent almost a half billion inflation-adjusted dollars in an attempt to build a reservation system named George -- as in "go ask George" -- before it had to scrap the project and start over.

But such failures were inevitable. Working together with early computer makers, airlines were pushing the envelope of business computing. Not just backroom end-of-the-month number crunching, but managing sales on the fly, electronically. Little did they realize their work would later be recognized as one of the earliest e-commerce applications.

Gumballs Over time, a sophisticated electronic distribution network grew up around reservation systems. Even bigger systems emerged. They consolidated information for many different airlines to permit one-stop shopping. Known as global distribution systems, these one-stop shopping machines became the neighborhood travel agent's best friend.

When the Internet arrived on the scene, it provided a new way to hook into this vast network. Today, whenever you shop on line for a plane ticket, you are quite probably linked to one of these titanic electronic gumball dispensers.

Increased use of the web has led to astonishing growth in the number of requests handled by global distribution systems. One of the world's largest now handles over a hundred trillion requests per year. That comes to almost 5000 per second. It's impossible to even imagine how many rooms filled with chalkboards it would take to manage this kind of activity.

When we think of flying, computers aren't typically the first machines that come to mind. Our eyes turn to all those airplanes. Yet commercial aviation would be a vast tangle, and it would be far more costly, if those machines weren't constantly fitting the incomprehensible jigsaw puzzle together for us.

I'm Andy Boyd, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Dr. Andrew Boyd is Chief Scientist and Senior Vice President at PROS, a provider of pricing and revenue optimization solutions. Dr. Boyd received his A.B. with Honors at Oberlin College with majors in Mathematics and Economics in 1981, and his Ph.D. in Operations Research from MIT in 1987. Prior to joining PROS, he enjoyed a successful ten year career as a university professor.

Much of the material in this essay was derived from years of fascinating conversations with people in the airline industry, to whom I offer my thanks. Special thanks to Al Ludwig for locating the information on the number of requests handled by the global distribution system Worldspan.

See also T. Petzinger, Jr., Hard Landing: The Epic Contest for Power and Profits That Plunged the Airlines into Chaos, (New York: Three Rivers Press, 1995).





The Engines of Our Ingenuity is Copyright © 1988-2005 by John H. Lienhard.