American Airlines cancelled hundreds of flights Sunday, its third consecutive day of cancellations. The airline was experiencing staff shortages that disrupted weekend plans for thousands of travelers.

American had cancelled more than 900 flights by Sunday afternoon, one-third of its day’s schedule, after having scrapped nearly 900 flights in the past two days, FlightAware tracking service said.

American spokeswoman said that the airline expected significant improvement starting Monday but there would be some residual impact from Saturday. According to FlightAware, American had already cancelled more than 100 Monday flights by Sunday afternoon.

American experienced difficulties Thursday and Friday when high winds caused the airline to be unable to use all of its runways. This made it difficult to position crews for future flights and caused disruptions. Over the weekend, the number of cancelled and delayed flights increased in both geographic and numerical range.

“To ensure we are taking care our customers and providing scheduling certainty to our crews,” David Seymour (chief operating officer of the airline) stated in a note to employees.

According to internal figures seen at The Associated Press, about two-thirds (or three quarters) of Sunday’s cancellations were caused by a shortage in flight attendants. Nearly all of the other cancellations were due a shortage pilots.

The debacle was similar in nature to the disruptions at Southwest Airlines that occurred in October. The twin failures raise grave concerns about the readiness of major airlines for the holiday travel season.

American claims it will.

Seymour stated that almost 1,800 flight attendants will return to work starting Monday, and at least 600 new employees will join the airline by the end. Seymour stated that the airline will also be hiring reservations agents and pilots in time for the holidays.

As a condition for billions of dollars in federal pandemic relief, airlines were prohibited from laying off employees during the pandemic. 19,000 Americans were temporarily furloughed when the money ran out last year. However, they reversed their decision once aid was restored. However, this didn’t stop airlines from offering cash incentives to employees and encouraging them to quit. American, Southwest, and other airlines are hiring people to replace those who have left by 2020.

American labor unions warned the airline for months about its inability to schedule enough flights. This meant that employees were spread too thin when bad weather disrupts air travel.

Dennis Tajer, a pilot for American Airlines and spokesman of the Allied Pilots Association, stated that the union has never seen so many cancellations after storms have passed.

He said, “Since spring, we have been warning about these post-weather management failures in recovery, and it’s just becoming worse.” “We remain very concerned about the uncertain nature of the winter holiday travel season.”

American scheduled approximately 2,600 flights Sunday, excluding regional affiliates flying as American Eagle. According to Cirium, the aviation-data firm Cirium, this number will jump to over 3,000 flights in eight days around Thanksgiving and early Christmas.

Southwest cancelled well over 2000 flights earlier in October due to disruptions caused by weather in Florida. These were further complicated by staff shortages. Southwest’s chief operating office stated that the airline is pursuing a “very aggressive hiring plan”, but it was not “still where we want to go with staffing, especially pilots.”