with: SAS Scandinavian Airlines (SK810, SK804, SK806), South African Airways (SA7965), Etihad Airways (EY7473, EY7528), Singapore Airlines (SQ2662), Air Canada (AC9941)
with: Finnair (AY5479, AY5513, AY5515, AY5431), British Airways (BA2273, BA179, BA115), Jet Airways (India) (9W5812)
with: Air Transat (TS565, TS265, TS293, TS209), Air Canada (AC1931), Deutsche Lufthansa (LH6716), Brussels Airlines (SN9629), United Airlines (UA8253)
with: Air Canada (AC6198, AC6186, AC6200), Austrian Airlines (OS452, OS458), United Airlines (UA9846), Japan Airlines (JL7729), British Airways (BA706)
with: British Airways (BA960, BA956, BA948, BA952, BA954), Cathay Pacific Airways (CX7163), American Airlines (AA6386), Japan Airlines (JL7713)
with: British Airways (BA912, BA902, BA916, BA904, BA910), Japan Airlines (JL7873, JL7821), American Airlines (AA6498)
with: Air Canada (AC6198, AC6186, AC6200), Austrian Airlines (OS452, OS458), United Airlines (UA9846), Japan Airlines (JL7729), British Airways (BA706)
with: Air Canada (AC849, AC859, AC857), Finnair (AY5999), British Airways (BA99), Iberia (IB7341), Ethiopian Airlines (ET1140), American Airlines (AA6213)
with: Singapore Airlines (SQ2149, SQ2145), Deutsche Lufthansa (LH959, LH955, LH953), United Airlines (UA9569, UA9562), ANA All Nippon Airways (NH5868)
with: Deutsche Lufthansa (LH943, LH947, LH949), United Airlines (UA9549), Austrian Airlines (OS7366, OS7374), ANA All Nippon Airways (NH5866), South African Airways (SA7507)
with: British Airways (BA960, BA956, BA948, BA952, BA954), Cathay Pacific Airways (CX7163), American Airlines (AA6386), Japan Airlines (JL7713)
with: Eurowings (EW469, EW461, EW465, EW355), Air Canada (AC6948, AC6952), United Airlines (UA9646, UA9671)
with: British Airways (BA912, BA902, BA916, BA904, BA910), Japan Airlines (JL7873, JL7821), American Airlines (AA6498)
with: Deutsche Lufthansa (LH2503, LH2501), Austrian Airlines (OS7376, OS7350, OS7358), South African Airways (SA7575), United Airlines (UA8753), ANA All Nippon Airways (NH5427)
with: American Airlines (AA135, AA109), Finnair (AY5785, AY4014), British Airways (BA1502), Fiji Airways (FJ5068), El Al Israel Airlines (LY8071), Virgin Atlantic Airways (VS7)
with: British Airways (BA676, BA680), American Airlines (AA6613, AA6465), Avianca (AV6616), Turkish Airlines (TK1984), AtlasGlobal (KK2002), Air Canada (AC6702)
with: United Airlines (UA929, UA928), Swiss International Air Lines (LX3044, LX3058), Brussels Airlines (SN9089), Air Canada (AC5357), Deutsche Lufthansa (LH9354), Austrian Airlines (OS7851)
with: British Airways (BA676, BA680), American Airlines (AA6613, AA6465), Avianca (AV6616), Turkish Airlines (TK1984), Air Canada (AC6702), bmi regional (BM6361)
with: Delta Air Lines (DL209), Air Canada (AC5649), Deutsche Lufthansa (LH7643), United Airlines (UA39), Virgin Atlantic Airways (VS4027)
with: American Airlines (AA6190), Finnair (AY5527), British Airways (BA287), Iberia (IB7445), Virgin Atlantic Airways (VS19), Aer Lingus Irish Airlines (EI8987), Aeroméxico (AM7672), Jet Airways (India) (9W5828)
History
United Airlines has its roots in the Varney Air Lines air mail service of Walter Varney. In 1926 the airline flew the first schedule airline service in the country's history.
During the September 11, 2001 terrorist attacks, two of hijacked airplanes were United Airlines aircraft. An airline industry slump, coupled with economic hardship, increasing oil prices, and higher labor costs, led to the company losing $2.14 billion in 2001.
In 2011 United merged with Continental Airlines.