Passengers will only use one terminal at Belfast-Aldergrove Airport, common to all flights. The airport building is inconspicuous and quite unsightly, but it is very easy to navigate.
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The terminal is divided into an arrivals area and a departures hall, both of which are on the ground floor. You have to take the escalator up to the first floor to get through security and on towards the departure gates.
Transfer between flights
Belfast is not primarily a transfer point and therefore the airport does not have the option of a direct transfer at all without leaving the transit area.
You always have to go through passport control, come out, walk between the arrivals and departures hall and check in again.
If you plan to transfer on your own in Belfast, expect a net transfer time from arrival to departure gate of approximately 60 minutes.