United’s Passengers Were Stuck, but Its C.E.O. Flew on a Private Plane

United Airlines appeared to restore more normal operations on Friday after a weeklong struggle to recover from flight delays and cancellations ahead of the busy Fourth of July holiday.

The airline’s disruptions began last weekend in the New York area. At the time, United blamed thunderstorms and federal air traffic control staffing shortages and inexperience. Other airlines suffered flight delays and cancellations at the time, too, but by Wednesday United’s problems stood out as they spread to its operations across the country.

Adding to the bad publicity for the airline, the company’s chief executive, Scott Kirby, on Wednesday took a private jet to Denver, where the airline has a hub, from Teterboro Airport, which is close to Newark Liberty International Airport, one of United’s biggest hubs. The airline said it did not pay for the trip and, in a statement on Friday, Mr. Kirby said he regretted taking that flight.

“Taking a private jet was the wrong decision because it was insensitive to our customers who were waiting to get home,” he said. “I sincerely apologize to our customers and our team members who have been working around the clock for several days — often through severe weather — to take care of our customers.”

United’s troubles began to improve in recent days. After canceling over a quarter of its flights on Tuesday and Wednesday, United scrubbed about 19 percent of its schedule on Thursday and about 8 percent by late afternoon on Friday, according to FlightAware, a flight tracking firm. Still, the number of flights the airline canceled on those two days eclipsed cancellations by other carriers.

United expressed optimism about its recovery on Friday. In a statement, the airline said that storms could present a challenge along the East Coast and in Denver and Chicago, but that United was “ready” for the busy weekend.

“Our reliability continues to improve, with far fewer cancellations today compared to previous days,” United said.

Pete Buttigieg, the transportation secretary, singled out the airline on Twitter on Thursday, sharing a chart that showed that other carriers had recovered from bad weather earlier in the week while United had not.

On Monday, Mr. Kirby told employees in a memo that the Federal Aviation Administration, which oversees air traffic control and is a part of the Transportation Department, had “failed” United over the weekend. Mr. Kirby similarly blamed air traffic control for delays last summer, later apologizing to Mr. Buttigieg for the way he had characterized that criticism in a letter to employees.

This week has been one of the busiest periods for air travel in years. The Transportation Security Administration reported screening more than 2.7 million people on Thursday, one of its busiest days since 2019. Only four other days have been busier since the pandemic began, all in recent weeks. AAA, the travel club, said it expected nearly 4.2 million people to fly this weekend, up 6.6 percent from 2019.

Throughout the week, United passengers have reported having to sleep in airports and stand in line for hours to rebook flights. Some travelers said they had to wait days to retrieve checked bags.

Elizabeth Rodriguez, traveling with her 12-year-old son, said in an interview on Friday that it had taken days longer than expected to get home to Fairfax, Va., from Texas. On Wednesday morning, just hours before they were scheduled to depart on a United flight from San Antonio International Airport, she was notified by text and through the airline’s mobile app that the flight had been canceled because of crew scheduling issues.

When Ms. Rodriguez called customer service to rebook, she was told there was a two-hour wait. With no other available flights to the Washington area that day, she booked a flight online departing the next day via Houston. After she landed in Houston on Thursday night, her flight to Reagan National Airport was delayed repeatedly into Friday morning.

“United Airlines handled this week poorly, was ill prepared and failed to be transparent with passengers throughout the entire process,” Ms. Rodriguez said. She added that testy gate agents had offered many reasons for the ordeal, including crew scheduling issues, weather and mechanical problems.

The airline handed out hotel vouchers for only some passengers on her flight, said Ms. Rodriguez, who ended up paying for a room herself. Her flight finally departed on Friday morning, 15 hours after its original departure time.

“I am so frustrated with delays, but even more so with how they treated people at the airport,” she said. “I don’t know if I will use United again.”

Her exasperation was similar to what passengers of Southwest Airlines felt over the winter holidays. Southwest canceled more than 10,000 flights in the four days after Christmas, or about 46 percent of its schedule. On United’s worst day this week, Tuesday, it canceled nearly 800 flights, or about 28 percent of its schedule.

The disruptions have left pilots and flight attendants frustrated, too. Many have had to wait on hold for hours to get reassignments after flights were canceled. Some flight attendants slept at airports, too, according to social media posts.

“Weather last weekend affected everyone, but United is the only airline still struggling to recover, and we know why,” Ken Diaz, president of the United chapter of the Association of Flight Attendants-CWA, which represents more than 25,000 United flight attendants, said in a statement on Thursday. “United management’s failure to properly staff crew schedulers, the flight attendant support team and more has exacerbated these operational issues.”

Mr. Diaz said United had “lost” crews in its system for days because of the breakdown. He also said that the union had warned management last year of problems that could contribute to more disruptions, but that the airline “charged ahead” with an ambitious flight schedule this summer. United used some of the union’s recommendations to get through the current disruption, including making changes to its schedule and agreeing to pay flight attendants three times their normal pay to pick up trips through next Thursday, Mr. Diaz said.

Pilots have expressed similar frustrations.

“It is United Airlines management that is failing our loyal customers by ignoring the warning signs and failing to properly plan,” Capt. Garth Thompson, president of the United chapter of the Air Line Pilots Association union, which represents more than 15,000 of the airline’s pilots, said in a statement.