The airline said it will try to move affected passengers to other aircraft models but that ultimately about 115 flights will be canceled per day because of the extension.
These cancellations may include flights on planes that are not Boeing 737 Max aircraft, in order to use the planes on Max routes that require coverage, the airline said.
The news comes a week after the FAA said a joint investigation with Boeing found that more than 300 planes may have been manufactured with faulty parts by a Boeing supplier.
The parts used on 737 Max and 737 NG planes “may be susceptible to premature failure or cracks,” the FAA said. It said it would mandate all affected parts to be removed and replaced within 10 days.
United Airlines and Southwest Airlines also include 737 Max planes in their fleets. Both airlines have canceled its flights into August.
The Boeing jet has been grounded since mid-March after an Ethiopian Airlines plane crashed. That catastrophe came five months after a similar crash involving a Lion Air flight in Indonesia.