United Airlines CEO Scott Kirby promised refunds to customers who did not want to fly during restrictions on flights imposed by U.S. transportation officials that are set to begin at the end of the week.

Transportation Secretary Sean Duffy announced in a Nov. 5 news conference that there will be a 10% reduction in flights at 40 major airports starting Friday, Nov. 7 due to impacts from the ongoing federal government shutdown. He did not specify when the reductions would end.

The drastic plan for flight reductions sent airlines scrambling to make significant reductions in flights in just 36 hours and passengers flooded airline customer service hotlines with concerns about air travel in the coming days.

Kirby wrote that any customer is eligible for a refund while the reductions are in effect "even if their flight isn't impacted" in a memo to employees provided to USA TODAY. The offer includes non-refundable and basic economy tickets.

He also said that the airline will make rolling updates to its schedule as the record-breaking government shutdown continues and will provide travelers "several days' advance notice" of changes to minimize disruption.