Flight disruptions continued Sunday but eased from the rocky start to Memorial Day weekend, a test for carriers as they gear up for a busy summer travel season after more than two years of the Covid pandemic.

Delta Air Lines led cancellations, disruptions it attributed to bad weather and “air traffic control actions” on Saturday. Hundreds of flights operated by Republic Airways, United Airlines, JetBlue Airways and American Airlines were also delayed Saturday.

Delta canceled 254 mainline flights, or 9% of its Saturday schedule, and 530 were delayed, almost a fifth of its schedule, according to flight-tracking site FlightAware. On Sunday, it canceled 153 flights, or 5%, while delays totaled 162, or 6% of the schedule.

Delta said that 87% of customers were rebooked on flights that departed within around 11 hours of their original time.

The Atlanta-based carrier last week said it would trim its schedule by 100 flights a day between July 1 through Aug. 7, around 2%, to give itself more wiggle room to handle disruptions.

Other carriers, including Alaska Airlines, JetBlue Airways and Spirit Airlines have also pared back schedules to better handle disruptions like bad weather and staffing shortages.

Getting the balance right is key for carriers as bookings recently jumped despite airfares that have surpassed pre-pandemic levels.