United Airlines will pull its 14 Boeing 737 Max aircraft from its schedules through 4 June as the US Federal Aviation Administration’s safety review of the grounded aircraft extends into 2020 and carriers remain uncertain when those fleets could be cleared to return to service.

The Chicago-based carrier had previously removed the Max from its schedule through 4 March.

The airline has 14 737 Max jets in storage, with 144 more of the type on order, according to Cirium fleets data. In total, United Airlines has 764 aircraft of various types in service.

American Airlines and Southwest Airlines, which have extended cancellations of their Max fleets through April, have removed the aircraft from their schedules one month at a time. United’s announcement departs from that month-by-month cancellation trend.

The airline will cancel up to 108 flights per day through June during the grounding, says United spokesman Frank Benenati tells Cirium on 20 December. The extended cancellation will help the network team plan the year ahead, he says.

“By moving the return to service date back more than just a month, as we have done previously throughout 2019, it allows us to have more certainty by providing our customers and our operation a firmer and more definitive timeline,” Benenati says. “We will better help our customers by reducing the number of our passengers we need to reassign to a new aircraft or rebook on a different flight.”

Like other airlines with Max fleets in storage, United has covered the capacity gap with measures including flying spare aircraft on flights originally scheduled for Max aircraft. The FAA grounded the 737 Max in March 2019.

Southwest has 34 737 Max airliners in storage and all its 262 on-order aircraft are Max jets, Cirium fleets data shows. American has 24 Max jets in storage and 76 on order.