Question: On which Portuguese island has the largest European airline by scheduled passengers flown had a base since 2015?
Related documents: [0]  [DOC] João Paulo II Airport (IATA: PDL, ICAO: LPPD) , named after Pope John Paul II, is an international airport located on the island of São Miguel, in the Portuguese archipelago of the Azores. Situated 2 km west of the city centre of Ponta Delgada, it is the primary (and busiest) airport in the Azores, as well as the fifth largest infrastructure managed by ANA Aeroportos de Portugal; with the construction of the terminal in 1995, by 2005 the airport served a total of 873,500 passengers. It has scheduled domestic flights to all islands of the Azores, plus Madeira and the mainland, namely (Lisbon, Porto and Faro). João Paulo II Airport also accommodates international flights to and from Europe and North America. The airport is the major hub for the SATA Group of airlines, which includes both inter-island SATA Air Açores and international Azores Airlines, and since April 2015 as a base for Ryanair. [END] 
[1]  [DOC] Ryanair Ltd. (/raɪə'ner/) is an Irish low-cost airline founded in 1984, headquartered in Swords, Dublin, Ireland, with its primary operational bases at Dublin and London Stansted airports. In 2016, Ryanair was the largest European airline by scheduled passengers flown, and carried more international passengers than any other airline. (, , NASDAQ: RYAAY ) [END] 
Answer: 
São Miguel
São Miguel