American Airlines Group Inc. is the largest airline internationally. This Delaware corporation's wholly-owned subsidiaries are American Airlines, Envoy Aviation Group , PSA Airlines and Piedmont Airlines. The company's primary business is to provide passenger and cargo services. American Airlines' hubs are at Charlotte, Chicago, Dallas/Fort Worth, London Heathrow, Los Angeles, Miami, New York, Philadelphia, Phoenix and Washington, D.C. Its partners gateways are in London, Madrid, Seattle/Tacoma, Sydney and TokyoLondon, Madrid, Seattle/Tacoma, Sydney and Tokyo. On domestic routes, the company competes with the likes of Alaska Airlines, Allegiant Air, Delta Air Lines, Frontier Airlines, Hawaiian Airlines, JetBlue Airways, Southwest Airlines, Spirit Airlines and United Airlines. The caarier also provides international service to Canada, Mexico, the Caribbean, Central and South America, Asia, Europe, Australia and New Zealand.