►SkyWest Airlines, which operates regional flights for United, Delta, American and Alaska under those airlines' names: 416 flights, or 17% of scheduled flights. Other regional feeder airlines, including Mesa Airlines, Envoy Air and Air Wisconsin, are also canceling dozens of Sunday flights. Mesa, which flies as American Eagle and United Express, has canceled 18% of its flights and Air Wisconsin, which flies as United Express, has canceled 16% of its flights.