In 1930, a merger of more than eighty minor airlines formed American Airlines. Robertson Aircraft Corporation and Colonial Air Transport are the two firms that gave birth to American Airlines. The former was founded in Missouri in 1921, and the two companies were merged in 1929 into The Aviation Corporation, a holding corporation. In 1930, this was rebranded as American Airways and turned into an operating corporation. When new legislation and the loss of postal contracts caused several airlines to reorganise in 1934, the company restructured its routes into a connected system and renamed American Airlines. The company expanded into an international carrier between 1970 and 2000, eventually purchasing Trans World Airlines in 2001.