Thousands of frustrated travelers waited in two-hour-long lines to pass through security Tuesday morning at Hartsfield-Jackson Atlanta International Airport (search), slowed by a rush of business and post-holiday passengers.

Until the crush cleared up by early afternoon, departing travelers at the country's busiest airport stood in a labyrinthine line that wound through ticketing and baggage claim areas and the food court before even nearing the security gate.

The line of ticketed passengers waiting to pass through security was so long it even backed up nontravelers who were just trying to reach the central atrium and food court area.

"We started outside, then the line went inside by the ticket counters, then back outside, then back inside, then we zigzagged around some more," said a worn-out Don Price of Moultrie, who was trying to get to the atrium to meet an arriving traveler.

Lines also have spilled outside at least twice in the last month.

By early afternoon, travelers' waiting time was down to about 10 minutes, but airport officials say people should expect more long lines on busy travel mornings throughout the summer.

Hartsfield-Jackson officials have warned for months they could not handle the summer travel crush without extra help from the federal Transportation Security Administration (search).

Part of the problem at Hartsfield is its "keyhole" security system that can quickly turn into a bottleneck. Rather than having security checkpoints on every concourse, like Los Angeles International Airport, passengers are screened at a single 18-lane checkpoint. Hartsfield-Jackson has just one terminal.

The airport has asked for more security lanes but the four additional lanes now being built haven't been completed. All 18 security lanes were in use Tuesday.

Airport managers are also waiting for 59 more screeners promised by federal authorities.

"We don't think anybody should have to wait in lines like this. We don't think you should have to wait in line more than 15 or 20 minutes — at the most," said airport spokeswoman Lanii Thomas, looking down on the lines from her fourth-floor office.

Travelers wondered whether security measures should be loosened now that air travel has bounced back to pre-9-11 levels.

Quincy Osborne, who was headed to the Cayman Islands for a vacation, expected to miss his flight even though he arrived at the airport three hours early.

"Not everyone should be considered a threat," he said. "Look, you see the elderly, little kids, expectant mothers. They should think of another way to do this."

Hartsfield-Jackson's passenger count this year is expected to top 81 million people, exceeding its record year in 2000.

Thomas warned that the four additional security lanes are the final ones planned, and that they won't be enough.

"We had all lanes open by five in the morning, and we still couldn't hold the line to an acceptable level," she said. "We are trying everything we can think of to speed up the process."