LOS ANGELES (CBS) — Airlines have been widely criticized for pocketing federal tax money during the FAA shutdown.

Now, at least one of them, Delta Airlines, is refunding that money to passengers.

The refunds will apply to passengers who bought their tickets before the FAA shutdown began on July 23, but traveled after that day.

During the shutdown, Airlines stopped collecting federal taxes that could add up to as much as $60 on a $300 round-trip ticket.

Most airlines kept their prices the same by raising fares to cover the taxes so travelers didn’t get any of the savings.

The airlines pocketed about $30 million a day in higher fares during the shutdown.