American Airlines is extending the cancellation of its Boeing 737 Max 8 flights from June until mid-August.
In a letter, the airline says the move is to “provide confidence” to customers during the peak summer travel season.
737 Max aircraft were grounded worldwide last month following fatal crashes involving Ethiopian Airlines and Indonesia’s Lion Air.
The jet’s anti-stall system has since come under scrutiny, and Boeing is now developing new software to address the problem.
According to BBC, senior officials at American Airlines are “confident” the upgrade would be approved by US aviation regulators before August 19th, despite its decision to ground its fleet of 24 planes until then.
Last week, Southwest Airlines made a similar move and United Airlines has also cancelled 737 Max 8 flights until June.