United Airlines announced Friday it was pushing back to September 4 the resumption of flights using the Boeing 737 MAX aircraft, grounded worldwide following two deadly crashes.
The US air carrier had said in December that it was eliminating flights using the aircraft from its schedule until June, and last month the company's commercial director said United had decided not to fly the aircraft this summer.
"We'll continue to monitor the regulatory process and nimbly make the necessary adjustments to our operation and our schedule to benefit our customers who are traveling with us," United said in a statement.
Boeing aims to get the model back in the air by the middle of the year, but has yet to receive the green light from US regulators.
Days after an Ethiopian Airlines 737 MAX crashed last March, killing all 157 occupants, the Boeing model was grounded worldwide.
The disaster followed the October 2018 crash of a 737 MAX operated by Lion Air in Indonesia, which killed 189 people. In both cases, the model's MCAS anti-stall flight system was implicated.