Phoenix is no stranger to heat, but the sweltering temperatures have gotten so bad that it's making it tough for some people to leave.
Higher temperatures make for thinner air, which is harder to generate lift from. Without the denser air pushing it upward, a plane's engines need to do more work to get it to takeoff speed.
Phoenix is just one area suffering under a record heat wave. Other western U.S. cities like Sacramento and San Francisco have seen record-high temperatures this week.