Question: in 2011 British Airways merged with the flag carrier airline of Spain founded in what year?

Context paragraphs:
Air India: Air India is the flag carrier airline of India.  It is owned by Air India Limited, a government-owned enterprise, and operates a fleet of Airbus and Boeing aircraft serving 90 domestic and international destinations.  The airline has its hub at Indira Gandhi International Airport, New Delhi, alongside several focus cities across India.  Air India is the largest international carrier out of India with an 18.6% market share.  Over 60 international destinations are served by Air India across four continents.  Additionally, the carrier is the third largest domestic airline in India in terms of passengers carried (after IndiGo and Jet Airways) with a market share of 13.5% as of July 2017.  The airline became the 27th member of Star Alliance on 11 July 2014.

Iberia (airline): Iberia ( ), legally incorporated as "Iberia, Líneas Aéreas de España, S.A. Operadora, Sociedad Unipersonal", is the flag carrier airline of Spain founded in 1927.  Based in Madrid, it operates an international network of services from its main base of Madrid-Barajas Airport.

British Airways: British Airways (BA) is the largest airline in the United Kingdom based on fleet size, or the second largest, behind easyJet, when measured by passengers carried.  The airline is based in Waterside near its main hub at London Heathrow Airport.  In January 2011 BA merged with Iberia, creating the International Airlines Group (IAG), a holding company registered in Madrid, Spain.  IAG is the world's third-largest airline group in terms of annual revenue and the second-largest in Europe.  It is listed on the London Stock Exchange and in the FTSE 100 Index.

Aer Lingus: Aer Lingus, ( , an anglicisation of the Irish "aerloingeas" meaning "air fleet") is the flag carrier airline of Ireland and the second-largest airline in Ireland.  Founded by the Irish government, it was privatised between 2006 and 2015 and it is now a wholly owned subsidiary of International Airlines Group (IAG), the parent company of British Airways and Iberia.  The airline's head office is on the grounds of Dublin Airport in Cloghran, County Dublin, Ireland.

Air Nicaragua: Nicaragua Airways is the potential future national flag carrier of Nicaragua.  Its main base is Augusto C. Sandino International Airport, Managua.  It is the first time in 20 years that Nicaragua will have a national flag carrier, after Aeronica ceased operations in 1991.  Since then, the flag carrier status was awarded to Nicaragüense de Aviación also known as NICA Airlines.  Several airlines had tried to become the Nicaraguan flag carrier like CAAL (Central American Airlines), SANSA (Servicios Aereos Nicaraguenses S.A.) but none of these survived a year.  Today even NICA Airlines (6Y) is registered as the national airline of Nicaragua, the only international flight it operated once (Managua to Miami) and is done under the TACA code (TA) as a full TACA Airlines flight.

Cayman Airways: Cayman Airways is the flag carrier airline of the British Overseas Territory of the Cayman Islands.  With its head office in Grand Cayman, it operates mainly as an international and domestic scheduled passenger carrier, with cargo services available on all routes.  Its operations are based at Owen Roberts International Airport (GCM) in George Town, Grand Cayman.  The airline also offers a limited charter service with a recent example being flights to and from Los Angeles.  Cayman Airways' slogan is "Those who fly us love us".

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.

Nigeria Airways: Nigeria Airways Ltd., more commonly known as "Nigeria Airways", was a Nigerian airline.  The company was founded in 1958 after the dissolution of West African Airways Corporation (WAAC).  It held the name "WAAC Nigeria" until 1971, when it was rebranded to the name it had until it ceased operations in 2003.  The government of Nigeria owned a majority of the airline (51%) until 1961, when it boosted its participation in the company to 100% and made it the country's flag carrier.  At the time of dissolution, the airline's headquarters were at Airways House in Abuja.  Operations were concentrated at Murtala Muhammed International Airport and served both domestic and international destinations mainly concentrated in West Africa; the network also had points in Europe, North America and Saudi Arabia.  The airline was managed by a number of foreign companies, including British Airways, the Dutch company KLM and South African Airways.

History of British Airways: British Airways (BA) is the flag carrier airline of the United Kingdom.  It is the largest airline in the UK based on fleet size, international flights and international destinations.  British Airways was considered the largest UK airline by passenger numbers from its creation in 1974 until 2008, when it was displaced by low-cost rival EasyJet.  Since its inception, British Airways has been centred at its main hub at London Heathrow Airport, with a second major hub at London Gatwick Airport.

Thai Airways Company: Thai Airways Company or Thai Airways (TAC; Thai: เดินอากาศไทย ) was the domestic flag carrier of Thailand.  Its main base was the domestic terminal at Don Mueang International Airport, then known as Bangkok International Airport.  Its head office was located in Pom Prap Sattru Phai, Bangkok.  In 1988 Thai Airways merged to become Thai Airways International (Thai: การบินไทย ).

Supporting paragraphs: British Airways Iberia (airline)
Answer: 1927