More than 3,500 flights canceled so far over Memorial Day weekend

Airline travelers are not only facing sticker shock this Memorial Day weekend

the kickoff to the summer travel season. They're also dealing with a pileup of flight cancellations.

More than 1,500 flights were canceled as of 9:50 p.m. EDT Saturday

according to flight tracking website FlightAware. That followed more than 2,300 cancellations on Friday.

Delta Air Lines suffered the most among U.S. airlines, with more than 250 flights

9% of its operations, eliminated on Saturday.

Hartsfield-Jackson International Airport in Atlanta, where Delta is based and has its largest hub

experienced heavy travel delays. On Saturday, 5% of the flights there were canceled, while 16% were delayed.

Delta noted in an email to The Associated Press that Saturday's cancellations were due to bad weather and "air traffic control actions