The Federal Aviation Administration reduced its flight cut requirements at 40 major airports on Friday, signaling progress in the country’s recovery from a severe air traffic controller shortage caused by the record 43-day government shutdown.

As of Saturday morning, airlines now only need to cancel 3% of their flights, down from the previous 6% requirement, according to the FAA and Department of Transportation. The agencies said improved staffing levels prompted the rollback after the shutdown ended Wednesday night.

The FAA first imposed the unprecedented restrictions on Nov. 7, citing safety concerns as absences mounted at air traffic facilities and airport towers. Controllers were among federal employees required to work without pay during the shutdown.

The flight cuts, which began at 4% before increasing to 6%, resulted in more than 11,800 cancellations between Nov. 7 and Friday. Cancellations peaked last Sunday at nearly 3,000 flights, representing about 10% of scheduled departures.

Boston Logan International Airport experienced 44 cancellations on Wednesday, 42 on Thursday and 26 on Friday, according to FlightAware.com. The number dropped significantly Saturday to nine.

Transportation Secretary Sean Duffy has said safety metrics must improve before the order is lifted entirely. While he hasn’t shared specific data, Duffy cited reports of planes getting too close in the air, increased runway incursions and pilot concerns about controller responses during the shutdown.

The situation began improving as more controllers returned to work following news of a possible shutdown deal in Congress. By Friday, only 2% of U.S. flights were canceled, according to aviation analytics firm Cirium.

Airlines are working to restore normal operations after days of disruptions that left planes rerouted and out of position. Airlines for America, the industry trade group, warned residual effects could continue for days.

Delta Air Lines CEO Ed Bastian expressed optimism about a quick recovery during an appearance on “CBS Mornings” after the shutdown ended, predicting a return to normalcy “a lot faster than people think.”

“And normal for us is an incredibly safe, incredibly reliable, great experience,” he said. “Thanksgiving is going to be a great holiday period of travel.”

The controller shortage predates the shutdown, but the 43-day closure worsened the problem. Duffy said that by the shutdown’s end, 15 to 20 controllers were retiring daily and some younger controllers were leaving the profession.

The FAA said it will continue monitoring the situation throughout the weekend to determine when normal operations can fully resume.

Associated Press material was used in this report.