"We wanted to fly to Terceira, but the proposal was refused," O'Leary said at a news conference in Lisbon. "No explanation was given."


On Friday, the secretary of state for transport said he could not yet say when low-cost airlines would start serving Terceira as they currently do Ponta Delgada, as well as Lisbon, Porto and Faro.


In the first four months of liberalisation of air transport to and from the Azores, heralding the arrival of Ryanair and Easyjet, more than 74,000 more passengers flew in and out than in the same period of 2014.


Tourism is seen as as one of the sectors with most potential in the region, which is one of Portugal's poorest.