By Adam Evans
The Head of Belfast International Airport says it could see a record year.
New airlines and routes mean 5.6 million people are due to pass through in 2017.
However, Graham Keddie is concerned about Air Passenger Duty and says it could stop airlines from investing here more.
He's told Q Radio News "every airline we speak to - they mention one thing; APD - top of the list. Michael O'Leary of Ryanair stood up in Belfast some weeks ago and when asked what was his major issue he didn't mention Brexit he said 'APD, APD, APD'".
Air Passenger Duty is an excise duty which charged to carry passengers flying from UK airports on an aircraft with take-off weight of more than ten tonnes or more than twenty seats for passengers.