The busiest airport in the United States without non-stop service to Asia, Charlotte Douglas International Airport (CLT) is US Airways' largest hub. About 44.3 million passengers passed through the airport in 2014. Other major carriers at the airport include Air Canada Express, American Airlines, Delta Air Lines, Frontier Airlines, Southwest Airlines and United Airlines. Passengers can fly non-stop to destinations across the United States, Canada and Mexico, as well as points in the Caribbean, Central America and Europe. The airport has four runways and one terminal with five concourses and more than 95 gates. Passenger amenities include restaurants, bars, coffee shops, retail stores, spa, charging stations, ATMs and a USO Center.