Question: The world's largest global airline alliances in which United is a founding member was founded when?

full_context: Document 1: US Airways Group: US Airways Group Inc. was an airline holding company based in Tempe, Arizona. US Airways Group operated US Airways, along with its subsidiaries PSA Airlines, Inc. and Piedmont Airlines, Inc., which are wholly owned but marketed under the branding of US Airways Express. It merged with America West Holdings Corporation, parent of America West Airlines, in 2005, and the combined company adopted the better-known US Airways name; the two airlines' operating certificates merged in 2007. It also operates additional companies that provide associated services. ACE Aviation Holdings, the Canadian parent of Air Canada retained a roughly 6.1% investment stake in US Airways Group. The route network covered destinations in 47 states, as well as international destinations.
Document 2: SkyTeam: SkyTeam is an airline alliance. Founded in June 2000, SkyTeam was the last of the three major airline alliances to be formed, the first two being Star Alliance and Oneworld. s of 2014 , SkyTeam consists of 20 carriers from five continents and operates with the slogan "Caring more about you". It also operates a cargo alliance named SkyTeam Cargo, which partners ten carriers, all of them SkyTeam members. Its centralised management team, "SkyTeam Central", is based at the World Trade Center Schiphol Airport on the grounds of Amsterdam Airport Schiphol in Haarlemmermeer, Netherlands.
Document 3: Star Alliance: Star Alliance is one of the world's largest global airline alliances. Founded on 14 May 1997, its current CEO is Jeffrey Goh and its headquarters is located in Frankfurt am Main, Germany. s of November 2016 , Star Alliance is the largest global alliance by passenger count with 689.98 million, ahead of SkyTeam (665.4 million) and Oneworld (557.4 million). Its slogan is "The Way The Earth Connects".
Document 4: United Airlines: United Airlines, Inc., commonly referred to as United, is a major U.S. airline headquartered in Chicago, Illinois. It is the world's third-largest airline when measured by revenue, after American Airlines and Delta Air Lines. United operates a large domestic and international route network, with an extensive presence in the Asia-Pacific region. United is a founding member of Star Alliance, the world's largest airline alliance. Regional service is operated by independent carriers under the brand name United Express. Its main competitors are American Airlines, Delta Air Lines, and Southwest Airlines.
Document 5: Lufthansa: Deutsche Lufthansa AG () (] ), commonly known as Lufthansa (sometimes also as "Lufthansa German Airlines"), is the largest German airline and, when combined with its subsidiaries, also the largest airline in Europe, in terms of fleet size, and the second largest airline in terms of passengers carried during 2016. The name of the company is derived from "Luft" 'air' and "Hansa", the Hanseatic League. Lufthansa is one of the five founding members of Star Alliance, the world's largest airline alliance, formed in 1997.
Document 6: Turkish Airlines: Turkish Airlines (Turkish: "Türk Hava Yolları") () is the national flag carrier airline of Turkey, headquartered at the Turkish Airlines General Management Building on the grounds of Atatürk Airport in Yeşilköy, Bakırköy, Istanbul. s of 2017 , it operates scheduled services to 302 destinations in Europe, Asia, Africa, and the Americas, making it the fourth-largest carrier in the world by number of destinations. It serves more destinations non-stop from a single airport than any other airline in Europe. Turkish Airlines flies to 120 countries, more than any other airline. With an operational fleet of fourteen cargo aircraft, the airline's cargo division serves 64 destinations. Istanbul Atatürk Airport is its main base, and there are secondary hubs at Esenboğa International Airport, Sabiha Gökçen International Airport, and Adnan Menderes Airport. Turkish Airlines has been a member of the Star Alliance network since 1 April 2008.
Document 7: American Airlines Group: American Airlines Group, Inc. is an American publicly traded airline holding company headquartered in Fort Worth, Texas. It was formed December 9, 2013, in the merger of AMR Corporation, the parent company of American Airlines, and US Airways Group, the parent company of US Airways. The airline groups together form the largest airline in the world, with more than 6,700 daily flights to 336 locations in 56 countries worldwide, about $40 billion in operating revenue, over 100,000 employees, and plans to take delivery of 607 new aircraft, including 517 narrowbody aircraft and 90 widebody international aircraft. The integration of American Airlines and US Airways was completed when the Federal Aviation Administration granted a single operating certificate for both carriers on April 8, 2015.
Document 8: 77 West Wacker Drive: 77 West Wacker Drive, previously the United Building, is an office building in the Loop, Chicago. Finished in 1992, the building rises to a height of 668 ft (204 m) with around 944000 sqft of interior space. The building, with 50 floors, was designed by Ricardo Bofill. It was formerly known as the RR Donnelley Building when the RR Donnelley printing company was the primary tenant. RR Donnelley moved its corporate headquarters to a different location in May 2005, and in 2007 the building became the corporate headquarters of United Airlines. The deal included naming rights to the building.
Document 9: UAL Corporation: UAL Corporation is the former name of United Continental Holdings, an airline holding company, incorporated in Delaware with headquarters in Chicago, Illinois. UAL held a 100 percent controlling interest in United Airlines, Inc., one of the world's largest air carriers, and is a founding member of the Star Alliance. It was announced on May 3, 2010 that UAL Corporation and Continental Airlines, Inc. would pursue a merger pending government approval. UAL Corporation would acquire Continental Airlines, Inc. and change its name to United Continental Holdings, Inc. (UCH). On October 1, 2010, UCH, formerly UAL Corporation, announced completion of the merger.
Document 10: International Airlines Group: International Consolidated Airlines Group, S.A., often shortened to IAG, is an Anglo-Spanish multinational airline holding company with its operational headquarters in London, England and its registered office in Madrid, Spain. It was formed in January 2011 after a merger agreement between British Airways and Iberia, the flag carrier airlines of the United Kingdom and Spain respectively. As British Airways was the larger company, those holding shares in British Airways at the time of the merger were given 55% of the shares in the new, merged company. British Airways and Iberia ceased to be independent companies and instead became 100% owned subsidiaries of IAG. It is the sixth-largest airline company in the world, producing €22.567 billion revenue in 2016. The company is listed on the London Stock Exchange and the Madrid Stock Exchange. It is a constituent of the FTSE 100 Index and IBEX 35 Index.
Document 11: United Continental Holdings: United Continental Holdings, Inc. (formerly UAL Corporation) is a publicly traded airline holding company headquartered in the Willis Tower in Chicago. UCH owns and operates United Airlines, Inc. The company is the successor of UAL Corporation, which agreed to change its name to United Continental Holdings in May 2010, when a merger agreement was reached between United and Continental Airlines. Its stock trades under the UAL symbol. To effect the merger, Continental shareholders received 1.05 shares of UAL stock for each Continental share, effectively meaning Continental was acquired by UAL Corporation; at the time of closing, it was estimated that United shareholders owned 55% of the merged entity and Continental shareholders owned 45%. The company or its subsidiary airlines also have several other subsidiaries. Once completely combined, United became the world's largest airline, as measured by revenue passenger miles. United is a founding member of the Star Alliance.
Document 12: Oneworld: Oneworld (marketed as oneworld; CRS: *O) is an airline alliance founded on 1 February 1999. The alliance's stated objective is to be the first-choice airline alliance for the world's frequent international travelers. Its central alliance office is currently based in New York City in the United States. Its member airlines include Air Berlin, American Airlines, British Airways, Cathay Pacific, Finnair, Iberia, Japan Airlines, LATAM Airlines, Malaysia Airlines, Qantas, Qatar Airways, Royal Jordanian, S7 Airlines and SriLankan Airlines, plus some 21 affiliated airlines. As of August 2016, Oneworld is the third largest global alliance in terms of passengers with more than 557.4 million passengers carried, behind Star Alliance (689.98 M) and SkyTeam (665.4 M). Its slogan is "An alliance of the world's leading airlines working as one."
Document 13: Alliance Jiu Jitsu: Alliance (pronounced "ah-lee-AHN-say" from the Brazilian origin, but "uh-LAHY-uhns" in the American/English form) is one of the most prominent Brazilian Jiu-Jitsu associations and the current defending World team champion, having won the titles at the World Championships from 2008-2016. They also won the World Championships back to back in 1998 and 1999. Alliance was founded by Romero "Jacare" Cavalcanti and his students: Fabio Gurgel, Alexandre Paiva, and Fernando Gurgel. Alliance Global headquarters is in Atlanta, Georgia at the Alliance Martial Arts Academy, where "Jacare" is the head instructor. Fabio Gurgel, also known as the "General", is the co-leader of Alliance and the head instructor at Alliance Sao Paulo (Sao Paulo, Brazil). Alexandre "Gigi" Paiva heads the third main Alliance academy in Rio de Janeiro, Brazil.
Document 14: Delta Air Lines: Delta Air Lines, Inc. ("Delta"; ) is a major American airline, with its headquarters and largest hub at Hartsfield–Jackson Atlanta International Airport in Atlanta, Georgia. The airline along with its subsidiaries and regional affiliates operate over 5,400 flights daily and serve an extensive domestic and international network that includes 319 destinations in 54 countries on six continents, as of October 2016. Delta is one of the four founding members of the SkyTeam airline alliance, and operates joint ventures with Air France-KLM, Alitalia, Korean Air, China Eastern Airlines, Virgin Atlantic, and Virgin Australia. Regional service is operated under the brand name Delta Connection.
Document 15: Berkshire Hathaway: Berkshire Hathaway Inc. is an American multinational conglomerate holding company headquartered in Omaha, Nebraska, United States. The company wholly owns GEICO, Long & Foster, BNSF Railway, Lubrizol, Fruit of the Loom, Helzberg Diamonds, FlightSafety International, Pampered Chef, and NetJets, and also owns 26.7% of the Kraft Heinz Company, and significant minority holdings in American Express (17.15%), The Coca-Cola Company (9.4%), Wells Fargo (9.9%), IBM (6.9%) and Apple (2.5%). Since 2016, the company has acquired large holdings in the major US airline carriers and is currently the largest shareholder in United Airlines and Delta Air Lines and a top 3 shareholder in Southwest Airlines and American Airlines. Berkshire Hathaway has averaged an annual growth in book value of 19.0% to its shareholders since 1965 (compared to 9.7% from the S&P 500 with dividends included for the same period), while employing large amounts of capital, and minimal debt.
ground_truth: 14 May 1997