CHICAGO (AP) _ Employees own 55 percent of UAL Corp. and its primary business, United Airlines, the world's No. 1 air carrier. UAL, based in Elk Grove Village, Ill., outside of Chicago, is one of the world's largest employee-controlled companies.

With hubs in Chicago, Denver, Los Angeles, Miami, San Francisco, and Washington, DC, and international hubs in Frankfurt, London, Tokyo and Toronto, United serves more than 130 destinations in 26 countries.

A brief history:

1929: Boeing and Pratt & Whitney merge their companies to form United Aircraft and Transport. Renamed United Air Lines in 1931, the New York-based company offers one of America's first coast-to-coast airline services.

1934: United's manufacturing and transportation divisions split. Former banker Bill Patterson becomes president of the latter, United Airlines, and moves it to the Chicago area.

1961: United buys Capital Airlines and becomes the nation's No. 1 airline.

1985: Pilots strike for 29 days.

1985: Purchases rental car company Hertz Corp.

1988, UAL sells its nonairline holdings, which include hotels and car rental operations, as well as 50 percent of its computer reservation partnership.

1989: Takeover bid by Los Angeles billionaire Marvin Davis and Coniston triggers unsuccessful buyout effort by United pilots, management, and British Airways.

1994: Stockholders approve an employee stock ownership plan, which cedes 55 percent of UAL to employees in exchange for $4.8 billion in wage concessions.

1995: Workers veto a proposed merger with US Airways.

1999: President James Goodwin, a 32-year United veteran, takes over as chairman and CEO.