Thousands of flights across the U.S. were delayed Monday, as severe thunderstorms in the South, Plains and Mississippi Valley disrupted traveling Americans during the Memorial Day weekend. As of 4:30 p.m. EDT on Monday, there were over 4,300 flight delays and more than 125 cancellations in and out of U.S. airports, according to FlightAware.

AAA predicted 45.1 million people across the country will travel at least 50 miles from home this weekend. The holiday’s previous domestic travel record of 44 million was set 20 years ago.