Delta had asked the FAA to waive minimum slot requirements at the congested airports because of a number of issues including airport construction, crew sick time, severe weather and air traffic control issues. The FAA said the approval "will support Delta's steps to make schedule adjustments and staff assignments to increase the reliability of its operations and minimize disruptions to travelers."

The relief covers flights June 1 through Sept. 5.

(Reporting by David Shepardson; Editing by Leslie Adler)