Question: Jeju Air is a founding member of the alliance formed in which month?

full_context: Document 1: HK Express: Hong Kong Express Airways Limited, or HK Express (), is a Hong Kong-based low-cost airline which provides scheduled air service to twenty-eight destinations in Asia, including China, Japan, Korea, Cambodia, Myanmar, Vietnam, U.S. Territories, Taiwan and Thailand. The airline's main hub at Hong Kong International Airport uses a fleet that consists exclusively of Airbus A320 family . The airline is one of the four founding members of the U-FLY Alliance.
Document 2: U-FLY Alliance: U-FLY Alliance () is the world's first alliance of low-cost carriers, formed in January 2016 between founding members HK Express, Lucky Air , Urumqi Air, and West Air. All four founding airlines are affiliated with the HNA Group, with a focus on Hong Kong, mainland China, and Southeast Asia, but they are currently seeking new members which are not affiliated with HNA Group. Eastar Jet, a South Korean low-cost carrier, joined the alliance on 27 July 2016.
Document 3: 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 4: Low-cost carrier: A low-cost carrier or low-cost airline (also known as "no-frills", "discount" or "budget" carrier or airline, or "LCC") is an airline that generally has lower fares and fewer comforts. To make up for revenue lost in decreased ticket prices, the airline may charge for extras such as food, priority boarding, seat allocating, and baggage. As of July 2014, the world's largest low-cost carrier is Southwest Airlines, which operates in the United States and some surrounding areas.
Document 5: Philippines AirAsia: Philippines AirAsia, Inc. (formerly Zest Airways, Inc. dba AirAsia Zest), is a low-cost airline based at Ninoy Aquino International Airport in Metro Manila in the Philippines. The airline is the Philippine affiliate of AirAsia, a low-cost airline based in Malaysia. The airline started as a joint venture between three Filipino investors and AirAsia Investments Ltd., a subsidiary of AirAsia Berhad.
Document 6: Vanilla Alliance: The Vanilla Alliance (French: "Alliance Vanille" ) is an airline alliance formed in September 2015 to improve air connectivity within the Indian Ocean region by strengthening cooperation between the airlines of Indian Ocean Commission members. Ultimately, the alliance wishes to increase tourism, trade, and business ties in the region. The founding members are Air Austral, Air Madagascar, Air Mauritius, Air Seychelles and Int'Air Îles.
Document 7: 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 8: Jetstar Pacific destinations: Jetstar Pacific Airlines Joint Stock Aviation Company (operating as Jetstar Pacific) is a low-cost airline headquartered in Tan Binh District, Ho Chi Minh City, Vietnam. With its hub at Tan Son Nhat International Airport, Ho Chi Minh City, operates scheduled domestic and international services along with charter flights.
Document 9: 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 10: West Air (China): West Airlines Co. Ltd. (), operating as West Air, is a low-cost airline based in New North Zone, Chongqing, People's Republic of China, operating a scheduled passenger network to 18 domestic destinations out of Chongqing Jiangbei International Airport and one international one to Changi Airport in Singapore. The company was established in March 2006 by its parent company Hainan Airlines, with the launch of scheduled services on 14 July 2010. The airline is one of the four the founding members of the U-FLY Alliance.
Document 11: Jeju Air destinations: The following is a list of destinations served by Jeju Air as of November 2015.
Document 12: Value Alliance: Value Alliance is an airline alliance formed in May 2016. It is the world's second alliance (after the U-FLY Alliance) to consist only of low-cost carriers (LCCs). However, it is the first pan-regional LCC alliance. It comprises seven Asia-Pacific airlines: Cebu Pacific, Jeju Air, Nok Air, NokScoot, Scoot, Tigerair Australia and Vanilla Air, along with Tigerair who merged with Scoot under the Scoot brand.
Document 13: Eastar Jet: Eastar Jet (ESR) () is a low-cost airline with its headquarters in Banghwa-dong, Gangseo-gu, Seoul, South Korea. On January 7, 2009, Eastar Jet made its maiden flight from Gimpo International Airport to Jeju International Airport. Now, the airline operates a scheduled passenger network to 14 destinations in eight countries. Its main base is Gimpo International Airport, with a hub at Jeju International Airport.
Document 14: Jeju Air: Jeju Air (), based in Jeju City, Jeju-do, South Korea, is a South Korean low-cost carrier, the first to be founded in the country. It offers scheduled domestic services between several cities in South Korea and Seoul as well as some destinations outside of Korea. It is also a founding member of the Value Alliance.
Document 15: Airline Allied Services: Airline Allied Services Limited (AASL) is Public Sector Undertaking (PSU) of the Government of India and is a subsidiary of Indian Airlines. Established in 1983, the company provides support services to Indian Airlines such as air transport services and manage airplane purchase, lease and sale transactions. As a subsidiary of Indian Airlines, AASL also provides air transport services under the name "Alliance Air". AASL is headquartered in New Delhi.
ground_truth: May 2016