The following airlines serve Colorado Springs Municipal COS Airport.
Airline Terminal
Allegiant Air Airlines, G4 Main Terminal
American Airlines, AA Main Terminal
Continental Airlines, CO Main Terminal
Delta Air Lines Airlines, DL Main Terminal
Expressjet Airlines, XE Main Terminal
Frontier Airlines, F9 Main Terminal
Northwest Airlines, NW Main Terminal
United Airlines, UA Main Terminal
US Airways Airlines, US Main Terminal

More details on airlines from the Colorado Springs Municipal Airport website.