Southwest’s Troubles Mount as Airline Scraps More Than Half of Its Flights

Chief Executive

Bob Jordan

told employees in a message Sunday evening that it might take a few more days to get back on track. “The winter storm was unprecedented all across our network. And we’ve got fallout from that—just trying to get the network back to normal,” he said.

Other airlines also had a rough run amid the harsh spell of weather that crossed the country starting last week.

Delta Air Lines Inc.

DAL 0.73%

canceled roughly 20% of its flights Saturday and Sunday.

Alaska Air Group Inc.

ALK 1.00%

canceled about 65% of its flights on Friday.

Spirit Airlines Inc.

SAVE -0.71%

on Sunday canceled 25% of its flights.

But other carriers didn’t have the same continuous levels of disruption. And several saw cancellation numbers ease Monday, while Southwest’s tally has climbed.

Southwest’s woes were due to a combination of the location of bad weather, the setup of Southwest’s flight routes and, executives and union leaders said, execution challenges.

The overarching issue was that the airline couldn’t get crews in the right place at the right time, leading it to cancel flights, according to a company memo Sunday from Chief Operating Officer

Andrew Watterson.

With a major presence in Denver and Chicago, which were beset by bone-chilling cold and wind, Southwest was affected early on. Planes froze overnight in Denver on Thursday night, and were unusable until midday Friday. Midway International Airport in Chicago ran out of space for de-icing, hobbling the airport even as O’Hare International Airport began to ramp back up.

Unlike some rivals that concentrate flying around central hubs, Southwest planes hopscotch around the country. That approach can make it hard to catch up when things start to go wrong early in the day—a problem that has also hobbled the airline’s recovery throughout the weekend and into this week.

Executives and union leaders said failures of process and technology contributed to the snafus.

“We have crews stuck, and scheduling doesn’t know where they are,” Casey Murray, head of the union that represents Southwest’s pilots, said Sunday. Pilots booked their own hotels when the airline didn’t assign them. Some flight attendants spent the night on cots in crew lounges, according to their union.

Crews rely on phone systems to call in for flight assignments, and many waited for hours on end for instructions before hitting limits on how many hours they can work without rest, union leaders said—a problem that executives acknowledged. Flights were canceled when they didn’t have a full complement of crew.

New and unexpected problems continued to crop up throughout the weekend, undermining the airline’s efforts to reset itself. Executives had been optimistic for improvements heading into Christmas Eve, according to messages to employees Friday.

But over that night its plans unraveled as it grappled with unexpected fog in San Diego, a staffing shortage at a fuel vendor in Denver, and the added workload from handling extra aircraft spending the night in Dallas—which had been part of an effort to relieve strains on airports further north.

“Even with crews picking up open trips, the disruption of our fleet and crew networks brought on by the impact of the storm had us starting today with hundreds of flights that needed crews,” said the COO, Mr. Watterson, in the message Sunday evening. That meant about 10% of the airline’s flying was canceled as it launched its operation Sunday, and the number continued to grow throughout that day.

Mr. Jordan, Southwest’s chief executive, said out-of-date systems are partly to blame.

“Part of what we’re suffering is a lack of tools,” Mr. Jordan told employees.

Mr. Watterson told employees Sunday night that the airline’s crew scheduling systems are “overmatched in situations of this scale,” and said the airline had already been in the process of upgrading those.

Southwest, based in Dallas, during the pandemic embarked on a major expansion into 18 new cities. As travel demand has roared back over the last year and a half, the carrier, like rivals, has had stumbles. But it has also ramped up hiring, with staffing levels now above 2019 levels, and is once again once again profitable. The airline this month said it would restore its quarterly dividend early next year.

Write to Alison Sider at alison.sider@wsj.com

Chief Executive

Bob Jordan

told employees in a message Sunday evening that it might take a few more days to get back on track. “The winter storm was unprecedented all across our network. And we’ve got fallout from that—just trying to get the network back to normal,” he said.

Other airlines also had a rough run amid the harsh spell of weather that crossed the country starting last week.

Delta Air Lines Inc.

DAL 0.73%

canceled roughly 20% of its flights Saturday and Sunday.

Alaska Air Group Inc.

ALK 1.00%

canceled about 65% of its flights on Friday.

Spirit Airlines Inc.

SAVE -0.71%

on Sunday canceled 25% of its flights.

But other carriers didn’t have the same continuous levels of disruption. And several saw cancellation numbers ease Monday, while Southwest’s tally has climbed.

Southwest’s woes were due to a combination of the location of bad weather, the setup of Southwest’s flight routes and, executives and union leaders said, execution challenges.

The overarching issue was that the airline couldn’t get crews in the right place at the right time, leading it to cancel flights, according to a company memo Sunday from Chief Operating Officer

Andrew Watterson.

With a major presence in Denver and Chicago, which were beset by bone-chilling cold and wind, Southwest was affected early on. Planes froze overnight in Denver on Thursday night, and were unusable until midday Friday. Midway International Airport in Chicago ran out of space for de-icing, hobbling the airport even as O’Hare International Airport began to ramp back up.

Unlike some rivals that concentrate flying around central hubs, Southwest planes hopscotch around the country. That approach can make it hard to catch up when things start to go wrong early in the day—a problem that has also hobbled the airline’s recovery throughout the weekend and into this week.

Executives and union leaders said failures of process and technology contributed to the snafus.

“We have crews stuck, and scheduling doesn’t know where they are,” Casey Murray, head of the union that represents Southwest’s pilots, said Sunday. Pilots booked their own hotels when the airline didn’t assign them. Some flight attendants spent the night on cots in crew lounges, according to their union.

Crews rely on phone systems to call in for flight assignments, and many waited for hours on end for instructions before hitting limits on how many hours they can work without rest, union leaders said—a problem that executives acknowledged. Flights were canceled when they didn’t have a full complement of crew.

New and unexpected problems continued to crop up throughout the weekend, undermining the airline’s efforts to reset itself. Executives had been optimistic for improvements heading into Christmas Eve, according to messages to employees Friday.

But over that night its plans unraveled as it grappled with unexpected fog in San Diego, a staffing shortage at a fuel vendor in Denver, and the added workload from handling extra aircraft spending the night in Dallas—which had been part of an effort to relieve strains on airports further north.

“Even with crews picking up open trips, the disruption of our fleet and crew networks brought on by the impact of the storm had us starting today with hundreds of flights that needed crews,” said the COO, Mr. Watterson, in the message Sunday evening. That meant about 10% of the airline’s flying was canceled as it launched its operation Sunday, and the number continued to grow throughout that day.

Mr. Jordan, Southwest’s chief executive, said out-of-date systems are partly to blame.

“Part of what we’re suffering is a lack of tools,” Mr. Jordan told employees.

Mr. Watterson told employees Sunday night that the airline’s crew scheduling systems are “overmatched in situations of this scale,” and said the airline had already been in the process of upgrading those.

Southwest, based in Dallas, during the pandemic embarked on a major expansion into 18 new cities. As travel demand has roared back over the last year and a half, the carrier, like rivals, has had stumbles. But it has also ramped up hiring, with staffing levels now above 2019 levels, and is once again once again profitable. The airline this month said it would restore its quarterly dividend early next year.

Write to Alison Sider at alison.sider@wsj.com