Flying on Southwest has been awful. The company has a fix: Fewer flights

New York(CNN Business) This summer, flying Southwest Airlines has been a toxic mix of canceled flights, long delays and disgruntled pilots and flight attendants. Apologizing to its passengers for its bad service, the company is promising to fix the problem by cutting the number of flights it operates this fall.

Southwest (LUV) had the worst on-time performance and the greatest percentage of canceled flights of any of the nation's four major airlines in June and July, according to flight tracking service Cirium. Passengers weren't the only fliers upset at Southwest: Unions for the pilots, flight attendants and mechanics have all voiced complaints about Southwest's operations.

"To any Southwest customer whose journey with us fell short of their expectation this summer, we offer our sincerest apologies," said a statement from outgoing Southwest CEO Gary Kelly. "We're confident these adjustments will create a more reliable travel experience."

Airlines are completing a strong summer, with planes full of travelers eager to get away after a year of lockdowns. But several airlines, most notably Southwest and American Airlines, have struggled to handle the increased demand.

The airline said it is reducing its schedule by 27 flights a day in September, taking it to an average of 3,304 flights a day across its system. For October it is reducing its schedule by an average of 162 flights a day -- an average of 3,420 flights.

Compared to its three larger rivals -- American Airlines (AAL), United (UAL) and Delta (DAL) -- Southwest flies the most daily flights. Those other carriers depend on so-called "regional airlines" to fly a great percentage of their flights, typically with smaller, feeder aircraft.

The airline also plans to make adjustments to its schedule for the remainder of the year, though those details have yet to be announced.

Severe understaffing

In addition to cutting flights, Southwest is in the process of hiring more workers. All of the major airlines reduced staff during the pandemic and are trying to rehire staff to meet the increased demand.

The pilots union at Southwest, which is planning "informational pickets" to express its displeasure with the airline, said it welcomes the announcement -- even though it means less flights for its members.

"We are pleased that Southwest has finally begun to hear the message that [the union] has been saying for months now — the current holiday schedule is not sustainable. The data shows it has the potential to be even worse than this summer has been," said Casey Murray, president of the Southwest Airlines Pilots Association. "Reduced schedules resulting in neutral/negative cash flows are not what we want. We want effective measures to reduce the waste and stress on our crews."

The airline's flight attendants are at "a breaking point" because of severe understaffing, according to Lyn Montgomery, president of the Transport Workers Union unit that represents the 15,400 Southwest flight attendants. She told CNN that the problem is partly because 1,000 flight attendants took early retirement offers in the early days of the pandemic.

Montgomery told CNN the airline has been regularly changing flight attendants' schedules, pushing them into extra-long days and weeks, and adding unstaffed flights to its September flying schedule. At the same time, flight attendants are on the front lines dealing with unruly passengers -- including one who the union has said knocked out two of a flight attendant's teeth.

Southwest has acknowledged some flight attendant staffing issues this summer. Around the July 4 holiday, it offered double pay to flight attendants who picked up extra trips. Other airlines have also struggled with staffing up as travel bounced back faster than expected.

Slowing demand

The cutback in schedule also comes at a time that the airlines are expecting air travel to slow after a busy summer.

They had been counting on a rebound in business travel as the summer travel season comes to its normal end on Labor Day. But with the rise of covid cases and many companies pushing back when their offices will reopen, the hopes for a rebound in business travel is also being pushed back.

Southwest warned investors three weeks ago that it has been seeing a slowdown in bookings and a rise in reservations being canceled and said that third quarter wouldn't be a strong as it previously believed. It referenced the growing impact of Covid on bookings in this week's statement.