(The Lion) — Hours-long delays on Sunday have led travelers to blast Southwest Airlines for issues at St. Louis Lambert International Airport, where lines to check baggage stretched outside to the highway.

“It was complete amateur hour today from Southwest airlines and Lambert,” said one user on X, Grant Mabie. “Not a good reflection on our city or a way to attract travelers or future conventions. One or more heads ought to roll.”

Others readily agreed, accusing Southwest of understaffing.

“Southwest was understaffed in St Louis yesterday after a conference… The check-in line was several hours long and snaked out down the ramp,” said another user. “Tons of missed flights and pissed off passengers.”

Southwest and the local airport both appeared to deflect blame to a Seventh-day Adventist convention, which reportedly attracted 50,000 people to the city.

Media accounts noted that an unusual number of people showed up at the airport early to check bags.

“The situation was exacerbated by most passengers needing to check bags and few of these passengers being a member of a program designed to expedite airport security, such as TSA Pre-check or CLEAR,” said a statement by the airport sent to local 5 On Your Side News.

Southwest, the largest carrier at the airport, also passed the buck to travelers in a statement to the local news outlet.

“A large number of passengers leaving a convention arrived to check in for their flights this morning,” said the airline. “We recommend that Customers check our website for up-to-date recommended arrival times.”

Local and national media were quick to parrot the statements’ tone in their own accounts of the delays, laying the blame entirely on convention-goers, tacitly exonerating the travel professionals at the airlines and the airport.

Some people online specifically blamed the Seventh-day Adventists attending their quinquennial conference in St. Louis for causing the problem.

“The Seventh Day Adventist organization can do a better job organizing delegates,” said Danielle Justenoire, a Jehovah’s Witness about the airport delays. “Don’t just say ‘All Adventists who want to come, just show up in St. Louis.’”

But a quick search of Southwest operations reveals the airline is most likely the main culprit in the fiasco.

In March, Southwest changed its long-cherished policy that allowed passengers to fly with checked bags for free, according to CNBC.

At the time of the bag policy change, Southwest executives warned that passengers could be facing delays because the company would have to charge for checked bags at the counter.

“With an additional step for customers to pay for bags at the ticket counter or kiosks, we have to plan for longer transaction and queue times,” the Southwest executives wrote, reported CNBC.

The Wall Street Journal estimated in May that the new baggage fees would add 40 seconds to an estimated 60-second transaction at the ticket counter, which compounds quickly.

For example, given those estimates, passenger number 50 in a line will wait an additional 33 minutes because of the baggage fees, passenger 100 an additional 66 minutes, and passenger 500 more than five hours. Assuming the five hour wait times mentioned by the media, Southwest needed to process a little under 500 more passengers, or 28 passengers more per gate, during their peak times.

Southwest accounts for about 59% of all traffic at Lambert International. With 18 gates at the airport, six flights per day departing from each gate could easily accommodate Southwest’s portion of the passengers, estimated at about 15,000 on Sunday, if managed properly.

Some passengers also complained travelers with later flights showed up early. But Southwest Airlines’ policy only allows check-in from three hours to 30 minutes before flight time.

Airports and airlines routinely manage check-in lines to stop early check-ins, preventing the types of bottlenecks that happened in St. Louis.

Photos from the airport shared by multiple media outlets showing passengers waiting near the road suggest those check-in policies weren’t followed.

“@SouthwestAir The check bag line was so long it lined the road down to the parking lot. It caused us to miss our flight,” said Melissa Nicholson. “Totally unacceptable, not to mention dangerous.”

Lambert said 25,917 passengers transited its 81 gates on Sunday with TSA screening a record number of passengers.