Southwest Airlines’ president and chief operating officer offered a fresh apology and explanation Thursday for why the carrier suffered widespread delays and cancellations over the weekend, saying “we are truly sorry.”

“I fully realize that any attempt at an explanation falls short of our ultimate goal of delivering you to your destination on time with our typical Southwest hospitality,” Mike Van de Ven wrote in a post on the company’s blog. “You expect and deserve better Customer Service from us, and we are committed to making necessary adjustments to deliver on that expectation.”

The problems showed how small disruptions can snowball as airlines seek to recover from the pandemic. Southwest said the disruptions began with bad weather and air traffic control issues in Florida early in the weekend. But then they continued, leading to more than 2,000 canceled flights that left passengers stranded and seeking help.

Southwest’s CEO Gary C. Kelly said the carrier’s operations were “much improved” by Tuesday and offered an apology in an interview with ABC’s “Good Morning America.”

Kelly said the problems in Florida hit Southwest particularly hard because about half of its planes go through the state.

“It just put the airline way behind on Friday,” Kelly said. “There were no ATC issues over the weekend — that’s absolutely true — but I think any industry expert knows that it takes several days if you have that large of an impact on the operation to get the airplanes where they need to be and then to match the crews up with that.”

Van de Ven said Orlando is one of Southwest’s biggest crew bases and was shut to traffic for seven hours Friday, stopping the airline from getting people and planes into its network.

The airline was still churning through complaints from passengers on Twitter, offering apologies and aid to those who needed it.

“We’re confident more favorable circumstances will prevail the next time we welcome you onboard,” one response from Southwest read.

The disruptions at Southwest are similar to problems the carrier and some of its competitors faced over the summer. Analysts say airlines’ staff cuts during the pandemic are leaving them vulnerable as they seek to welcome travelers back. Kelly said that Southwest had “moderated” its schedule and was planning to hire more but that the airline was continuing to face higher rates of absenteeism because of the ongoing pandemic.

Van de Ven said hiring was the company’s “number one focus” and that it was seeking to bring on 5,000 new employees.

“We continue to evaluate potential network schedule changes to mitigate operational risks as we head into the holidays,” he wrote. “There is certainly more work to be done as we approach November, and our Teams are dedicated to doing that work to support a reliable operation.”

Kelly announced in June that he plans to retire as Southwest’s chief executive early next year but will continue at the company as executive chairman of its board. He will be replaced by Robert E. Jordan, a longtime executive at the airline.

Some leading conservatives claimed the disruptions were caused by pilots protesting Southwest’s coronavirus vaccine mandate. There was no evidence that was the case, and the airline, its pilots union and the government all pushed back against the claims.

“To be clear: None of the information from Southwest, its pilots union, or the FAA indicates that this weekend’s cancellations were related to vaccine mandates,” the Federal Aviation Administration wrote in a tweet Monday evening.

On Monday, the Southwest Airlines Pilots Association circulated an analysis of the weekend and long-term staffing trends that showed no indication that any unsanctioned protests were a cause of the disruptions. The union found that sick rates for October were broadly consistent with recent months. There was also evidence that pilots were continuing to step forward to take on extra flights.

“If there was some sorts of grass-roots effort, they definitely wouldn’t be doing that,” said Amy Robinson, a spokeswoman for the union.

On Sunday the union found that a large number of pilots were on “dead head” flights — a sign that the airline was pushing to get them back in position for the coming week.

At the same time, the union said longer-term issues are taking a toll on pilots. It said crews are stretched thin by Southwest’s current schedule, describing “chronic manning problems and cumulative fatigue that have occurred since June.”

“The sick rate is slowly creeping up as our crews continue to get worn down by the operation,” the union said.

Air travel rebounded more quickly from the coronavirus than some analysts had predicted, putting unexpected pressure on airlines. The spread of the delta variant and rising case numbers blunted some of the recovery, and while analysts at Bank of America said this week that they expect the coming holiday season to be “strong,” they noted that Southwest and Spirit Airlines had pared back flying to ward off further disruptions.