The airline has grounded all of the 737 Max planes in its fleet until Nov. 3, about a month later than was previously expected. In total, United expects to cancel over 8,000 flights over the next four months.
The news comes one month after a joint investigation of Boeing and the Federal Aviation Administration found over 300 planes worldwide may include parts that were improperly manufactured by a Boeing supplier.
United is not the only airline to announce extensions to the grounding of its Boeing jets. American Airlines announced its own extension in June, keeping the planes earthbound until Sept. 3 and canceling about 115 flights per day.
“For more than 90 years, the safety of our customers and employees at United has come first,” United said in a statement. “Which is why we have cooperated fully with the FAA’s independent review of the MAX aircraft, and we won’t put our customers and employees on that plane until regulators make their own independent assessment that it is safe to do so.”
The Boeing jets have been grounded since mid-March, when an Ethiopian Airlines plane crash killed 157 people. It was the second of two fatal crashes involving the 737 Max model in a five-month period.