Low-cost airlines are hot, and they demand a unique design strategy that accounts for rapidly changing market conditions.

Leading low-cost airlines with a preference for small, inexpensive airports are now the largest airlines in the United States and Europe, according to an MIT expert on airport design and operations, who said that airport planners in major metropolitan areas need to accept this paradigm shift and build flexibility into airport design.

Professor Richard de Neufville of MIT’s department of civil and environmental engineering said that airport planners have been slow to grasp the reality that the business model of their largest customers has changed dramatically. Low-cost airlines require terminals about half the size of those of the legacy airlines because they use space more intensively, share gate lounges, and have few or no retail shops and restaurants. The reduced commercial activity results in fewer airport employees going through security checks and helps cuts passenger turnaround time in half.

“Airport planners are still building airports with fancy architecture and lots of retail space, but the low-cost airlines often won’t use them. And the low-cost airlines are not necessarily small anymore; they are a growing sector that represents the future. They want smaller, cheaper airports that increase efficiency,” said de Neufville.In a recent issue of Transportation Planning and Technology, de Neufville recommends flexible design that can account for changing market conditions such as major airlines going out of business, air traffic patterns, and passenger distribution. The solution is to think through likely possible scenarios, anticipate responses, and incorporate maneuverability into design and operations, according to de Neufville.

He notes that the new JetBlue terminal at New York’s JFK Airport will serve twice the number of passengers (20 million) as the recently built international terminal, using just half the space. The new building will cost about the same as Delta’s new terminal at Logan Airport (roughly half a billion dollars), but it will serve four times as many passengers. At Logan, JetBlue processes about half a million passengers per gate annually, about twice the number of its neighbor, Delta.