Changes are coming to the boarding process for economy class passengers. United Airlines will board passengers in economy class, prioritizing window seats over aisle seats starting next week, a move designed to reduce the time planes spend on the ground. The airline said in an internal memo that it will implement the plan on October 26.

The plan, called WILMA, would reduce boarding time by up to two minutes. Variations of the WILMA approach have existed for many years. “Distribute people along the aisle of the plane so that more people can store their luggage at the same time. That’s the main thing that speeds up the boarding process,” said Jason Steffen, an associate professor of physics at the University of Nevada, Las Vegas, who designed his own boarding model a decade ago.

The change will begin with passengers in the fourth boarding group. First and business class customers will see no changes to their routine, and there will be no changes for those with priority boarding privileges, including travelers with disabilities, unaccompanied minors, active-duty military and families with children ages 2 and younger.

Chicago-based United said that when multiple customers are on the same economy reservation, such as families, they will be allowed to board together. The new policy will be used on domestic flights and some international flights.

Airlines have been searching for the perfect boarding process for a long time. Even Orville and Wilbur Wright flipped a coin to see who had the only seat in their flying machine. United is making changes now because, he says, the average boarding time has increased by two minutes since 2019.

Adjustments to the boarding process have increased since airlines began charging fees for checked baggage more than a decade ago. Those fees encourage passengers to bring carry-on luggage, which generally remains free except on low-cost airlines. “Any time you have to fight with luggage over your head, things slow down,” Steffen said.

Two minutes doesn’t make much difference on a transatlantic flight, but on shorter routes with heavy traffic, delays tend to accumulate, delaying last-minute flights increasingly. If a few passengers dawdle while they put away their bags and find their seats, it can make the difference between a flight arriving on time or late in official government statistics.

The last passengers to board run the risk that there will be no space for their carry-on luggage in the overhead compartments. That leads passengers in late boarding groups to crowd the gate area so they can get in line before everyone else.