Airlines have canceled more than 1,100 U.S. flights since Friday and nearly 11,000 were delayed, a tough start to a busy holiday weekend after a messy spring for air travel angered passengers and drew sharp criticism from Washington.

On Friday, the delays included close to 1,000 American Airlines flights, nearly 30% of the carrier’s mainline schedule for the day, and 784 Delta flights, a quarter of the airline’s schedule, according to a tally from FlightAware. Thunderstorms delayed many flights at some of the country’s busiest hubs. Delays eased on Saturday but topped 3,000, less than half of Friday’s.

Already this year, the rate of flight cancellations and delays in June was higher than before the pandemic as a result of bad weather and staffing shortages. And airlines and federal officials have been scrambling to ease frustrations ahead of the busy holiday weekend.

This week, Delta took the unusual step of allowing travelers to change flights for free, without paying a difference in fare, if they can fly outside of the busy July 1-4 weekend, anytime through July 8. JetBlue Airways offered attendance bonuses for flight attendants this spring to ensure solid staffing. American Airlines regional airline Envoy is offering pilots triple pay to pick up extra trips through July.... Read More: CNBC