A Southwest Airlines Boeing 737-7H4 jet rolls for the gate after landing at Midway International Airport in Chicago, Illinois on April 6, 2021.

Kamil Krzaczynski | AFP | Getty Images

Southwest Airlines Apologized to workers Friday after their unions complained about stressful schedules this summer, saying they would consider changing dates for later this year.

The airline has added more flights to its schedule compared to some of its competitors to take advantage of increasing travel demand.

The increase in bookings was a welcome change compared to “a year ago, but we have to be honest with ourselves: It also put a strain on our operations and put a heavy burden on you all. And I’m really sorry,” wrote COO Mike Van de Ven in an employee notice viewed by CNBC.

Staff shortages have exacerbated problems such as bad weather for some airlines this summer and contributed to flight cancellations and delays. Southwest had a 64% punctuality rate between June 1 and August 18, less than American, delta and United, according to information from Cirium.

Van de Ven said the airline is continuing to evaluate our fourth quarter flight schedules and we are seriously reviewing flight altitudes to ensure our flying matches the personnel required to operate in this more complicated COVID environment.

Southwest declined to comment, but TWU Local 556, which represents the airline’s flight attendants, told members late Friday that the airline had reversed its course of adding an additional 720 crew assignments to its September plans.

The Southwest Pilots Union said Thursday it was Consideration of picket lines at US airports over Thanksgiving and Christmas to protest over crowded schedules, a lack of hotels and dining options, and other issues. Flight attendants raised similar issues this week.

“We will not follow our traditional staffing models as we will reassess our current situation in October, November and December,” wrote Van de Ven. “You come first.

The airline said earlier this week that it was struggling to hire new staff and was offering bonuses worth about. at $ 300 for employee referrals.

Southwest “continues to invest in a very aggressive hiring plan, even on a reduced schedule,” said Van de Ven.

Earlier this month the company did cut its sales forecast, which blames the rapidly expanding Covid-19 Delta variant for a decline in bookings and an increase in cancellations.

In this week, Spirit Airlines said it will cut some of its flight schedules for the remainder of the third quarter after more than 2,800 cancellations cost the company approximately $ 50 million.