On which Portuguese island has the largest European airline by scheduled passengers flown had a base since 2015?
João Paulo II Airport:  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. Ryanair:  In 2016, Ryanair was the largest European airline by scheduled passengers flown, and carried more international passengers than any other airline.
i don't know