According to CoinMeta, data from the flight tracking website FlightAware shows that over 700 flights entering or leaving the United States were canceled on Saturday. As of 7:45 p.m. Eastern Time, Delta Air Lines canceled 5% of their flights, United Airlines canceled 4% of their flights, and American Airlines canceled 2% of their flights. Airlines also often decide to cancel flights in advance for various reasons, including weather, maintenance issues, or crew scheduling.