The FAA will investigate airlines that might not have complied with a flight-reduction requirement imposed during the final days of the directive earlier this month.
"We will be sending out letters of investigation to any airlines that we don't feel lived up to the requirement to reduce capacity." FAA administrator Bryan Bedford said during a press conference at Newark Airport on Nov. 24. "That's going to be an ongoing investigation."
Transportation Secretary Sean Duffy, speaking at the same event, added that there needs to be accountability.
"When we have a directive from the FAA, we need our airlines to comply with it," he said.
The flight-reduction order required airlines to reduce operations at 39 commercial airports because of air traffic controller fatigue during the federal government shutdown. A spike in call-outs by air traffic controllers -- who weren't receiving paychecks during the shutdown -- was putting strain on the controllers who were showing up to work, the FAA said.
The directive began with reductions of 4% on Nov. 7, then 6% on Nov. 11. With the shutdown having ended on Nov. 12, the FAA lowered the capacity cuts to 3% on Nov. 15 and ended them on Nov. 17.
Low cancellations rates on Nov. 15 and Nov. 16 suggest that at least some airlines disregarded the reduction order on that final weekend. According to a Cirium analysis, the cancellation rate over the two days was well below 1%, including 0.25% on Nov. 16.