American Airlines announced it is extending a cancellation on some of its flights into early June due to the continued removal of the Boeing 737 MAX from service. The cancellations will affect 90 flights a day. Southwest Airlines, which also flies Boeing 737 MAX aircraft, took similar measures last month.

The ongoing disruption in air travel comes as Boeing apologized last week for the fatal crashes of two MAX 8 aircraft in recent months—last month’s Ethiopian Airlines Flight 302 and Indonesia’s Lion Air Flight 610 in October—which together killed nearly 350 people. The first American wrongful death lawsuit has been brought, and faulty software is believed to be have played a role in both crashes.