These passengers now faced longer travel times, increased costs and falling rental yields.
Ann Wright of Head of International Development at Primelocation International, said: "Ryanair makes a healthy profit from those customers who regularly use the airline throughout the warmer months. They should repay that loyalty by maintaining a reasonable level of service at quieter times of the year.
"We are still seeing interest from buyers looking to secure a second home abroad – our recent visitor survey reported that 70% of respondents were still actively looking to buy an overseas property.
"However, the threat of significant route cuts could cause many to reconsider their purchase, while those who already own a home abroad will be faced with limited access and rising travel costs."
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