American Airlines canceled nearly 340 flights on Monday, amounting to 6% of its schedule for the day.
The cancellations come on top of the 1,950 flights the carrier canceled between Friday and Sunday.
Over the weekend, American chief operating officer David Seymour told airline employees that the cancellations had been precipitated by high winds on Thursday in Dallas as well as other weather issues throughout the airline's system. Those problems, in turn, led to staffing problems as crew members ended up out of their usual flight sequences.
Seymour noted that 1,800 American flight attendants were scheduled to return from leave by Dec. 1, and that more than 600 new flight attendants would be hired by the end of the year. In total, American anticipates hiring 4,000 staffers during the fourth quarter, Seymour added.
Tight staffing also plagued Southwest Airlines in early October when it cancelled more than 2,400 flights in four days.
AA says there was no vax protest
In a posting Monday on the airline's Saleslink portal for the travel trade, American Airlines chief customer officer Alison Taylor and vice president of global sales Kyle Mabry addressed questions about whether the operational meltdown was caused by employee actions in protest to the Covid-19 vaccine mandate American has put in place.
"The vast majority of our team is already vaccinated, and you can rest assured our team is eager to take care of you and your travelers," the executives said.
Nevertheless, the Association of Professional Flight Attendants, which represents American flight attendants, did put out a missive on Saturday reminding reserve flight attendants that American cannot require them to accept an assignment would put them over their monthly maximum of 90 hours.
"The fact that there is inadequate staffing to cover the operation as it is currently structured is not the fault of flight attendants," the letter reads.
American canceled 343 flights on Friday, 548 flights on Saturday and 1,060 flights on Sunday.
American spokeswoman Laura Masvidal said the carrier expected considerable operational improvement on Monday but with some residual impact from the weekend.