Continental Airlines (IATA: CO, ICAO: COA, Callsign: CONTINENTAL) is an American airline based and headquartered in Continental Center I in Downtown Houston, Texas. It is the fourth-largest airline in the US based on revenue passenger miles. Continental operates flights to destinations throughout the U.S., Canada, Latin America, Europe, and the Asia-Pacific regions. Principal operations are from its three hubs at Newark Liberty International Airport, George Bush Intercontinental Airport, and Cleveland Hopkins International Airport.