Shuttle America Corporation was a regional airline in the United States based in Indianapolis, Indiana,. It fed United Airlines flights at Chicago O'Hare International Airport and Houston George Bush Intercontinental Airport under the United Express brand, as well as Delta Air Lines flights at Atlanta, New York-LaGuardia, and New York-JFK under the Delta Connection brand. Shuttle America also operated two of three Delta Shuttle East Coast routes, serving Washington, D.C., and Chicago from New York-LaGuardia.
SOURCE: Wikipedia