One of the thorniest issues for any airline is how to get people onto planes in a quick and orderly way while also giving privileged status to those who spend the most.
It doesn't help that flights on popular routes are often full these days, or that many passengers are schlepping carry-ons built to maximum dimensions.
The tension between crowd-handling efficiency and tiered service is one reason Atlanta giant Delta Air Lines is tweaking the boarding process at its home hub at Hartsfield-Jackson International Airport.
"It's easing that crowd flow," said Delta spokeswoman Ashton Morrow, who said boarding time is reduced by 30 to 60 seconds with the new system — a small-sounding but significant gain in an operation the size of Delta's. At the same time, she added, "loyalty is still sort of how we've built our process. That's definitely not changing."
At five gates on Concourse B in Atlanta, Delta passengers line up in four parallel lanes at marked pillars. They will continue to board by zone.
The lanes are intended to instill some order in the waiting area and deter people from spilling into the busy walkway, the airline says.
They could also help reduce the number of "gate lice" — a frequent flier nickname for people who crowd near the jetway door long before their group is called.
The lines also create a separate area for premium customers, and do the same for passengers who need special assistance, according to Delta.