with: Singapore Airlines (SQ2149, SQ2145), Deutsche Lufthansa (LH959, LH955, LH953), United Airlines (UA9569, UA9562), ANA All Nippon Airways (NH5868)
with: British Airways (BA836, BA826, BA834, BA838, BA824), S7 Airlines (S74709), American Airlines (AA6770), Japan Airlines (JL7825)
with: British Airways (BA912, BA902, BA916, BA904, BA910), Japan Airlines (JL7873, JL7821), American Airlines (AA6498)
with: British Airways (BA738, BA730, BA728, BA724, BA736), LATAM Chile (LA5571, LA5561), Japan Airlines (JL7707)
with: British Airways (BA676, BA680), American Airlines (AA6613, AA6465), Avianca (AV6616), Turkish Airlines (TK1984), Air Canada (AC6702), bmi regional (BM6361)
with: American Airlines (AA6753, AA6445), British Airways (BA51, BA57, BA55), Virgin Atlantic Airways (VS461), Air Canada (AC6852), Finnair (AY5945)
with: American Airlines (AA135, AA109), Finnair (AY5785, AY4014), British Airways (BA1502), Fiji Airways (FJ5068), El Al Israel Airlines (LY8071), Virgin Atlantic Airways (VS7)
with: Japan Airlines (JL7733, JL7793), Finnair (AY5984), British Airways (BA504, BA500), Cathay Pacific Airways (CX7203), Qatar Airways (QR5912), TAP Air Portugal (TP1357)
with: British Airways (BA960, BA956, BA948, BA952, BA954), Cathay Pacific Airways (CX7163), American Airlines (AA6386), Japan Airlines (JL7713)
with: SAS Scandinavian Airlines (SK810, SK804, SK806), South African Airways (SA7965), Etihad Airways (EY7473, EY7528), Singapore Airlines (SQ2662), Air Canada (AC9941)
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: British Airways (BA716, BA718, BA710, BA712), LATAM Chile (LA5580), American Airlines (AA6565, AA6354), Japan Airlines (JL6533)
with: Aer Lingus Irish Airlines (EI211, EI203, EI205), British Airways (BA2081, BA2073, BA6165), Etihad Airways (EY5162, EY7975)
with: British Airways (BA1423, BA1419, BA1417), Qatar Airways (QR5994, QR5992), Qantas Airways (QF3548), Japan Airlines (JL7126), American Airlines (AA6396)
with: Deutsche Lufthansa (LH2503, LH2501), Austrian Airlines (OS7376, OS7350, OS7358), South African Airways (SA7575), United Airlines (UA8753), ANA All Nippon Airways (NH5427)
with: Air Transat (TS565, TS265, TS293, TS209), Air Canada (AC1931), Deutsche Lufthansa (LH6716), Brussels Airlines (SN9629), United Airlines (UA8253)
with: Westjet (WS31), Air Transat (TS725, TS225, TS183, TS325, TS525), Air Canada (AC1939), Deutsche Lufthansa (LH6746)
with: Iberia (IB7368), British Airways (BA155), Air Canada (AC6512, AC6510), Egyptair (MS778, MS780), TAP Air Portugal (TP7017), United Airlines (UA7718)
with: Finnair (AY5479, AY5513, AY5515, AY5431), British Airways (BA2273, BA179, BA115), Jet Airways (India) (9W5812)
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.