7,000 flight cancellations disrupt Memorial Day weekend travel

May 30 (UPI) -- Travelers were left stranded Memorial Day weekend after airlines canceled more than 7,000 flights worldwide over a four-day span.

According to flight tracking website FlightAware, 1,580 more flights were canceled Monday. That followed 1,640 cancellations on Sunday, 1,500 on Saturday and 2,300 on Friday.

Delta Air lines canceled the most flights with 500 domestic and international flights grounded throughout the holiday weekend. The Atlanta-based airline blamed bad weather in the southeastern and northeastern United States, along with "air traffic control actions."

The airline promised to issue travel waivers to those affected.

American Airlines, meanwhile, canceled 117 flights on Monday, accounting for 3% of its operations.

AAA estimated 3 million Americans would travel by air over the holiday weekend and that number is expected to increase in June.

As COVID-19 travel restrictions ease, airlines are bracing for bigger crowds this summer. The number of travelers could surpass 2019 pre-pandemic levels as airlines struggle to keep enough employees on board.

Alaska Airlines has reduced its schedule by about 2% through June to match "pilot capacity," while JetBlue is cutting 8% to 10% of its summer schedule.

On Thursday, Delta announced on its website it would cut 100 daily departures from July 1 to Aug. 7 in parts of the United States and Latin America.

"More than any time in our history, the various factors currently impacting our operation -- weather and air traffic control, vendor staffing, increased COVID case rates contributing to higher-than-planned unscheduled absences in some work groups -- are resulting in an operation that isn't consistently up to the standards Delta has set for the industry in recent years," Delta's Chief Customer Experience Officer Allison Ausband said in a post.

"Based on our projections, summer travel isn't just heating up, it will be on fire," Paula Twidale, senior vice president of AAA Travel, said in a statement. "People are overdue for a vacation, and they are looking to catch-up on some much-needed R&R in the coming months."