United Airlines, founded in 1934, is one of the largest airline carriers in the United States. It offers scheduled passenger and airfreight services to more than 200 cities throughout the United States, Canada, Mexico, and Latin America. The services offered by the company include ground handling, non-routine airframe and engine maintenance, and aircraft parts and equipment. It operates more than 3,500 flights a day through United Airlines, United Express and Ted airliners from its hubs in Los Angeles, San Francisco, Denver, Chicago and Washington. United Express also offers Economy and Mileage Plus plans, and United First services to regular passengers. Its subsidiary, United Cargo, offers customers domestic and international shipping services for small packages and heavy freight.