Dublin Airport: Record numbers of NI passengers
Figures released on Thursday by Dublin Airport suggest the number of people from Northern Ireland using its routes have hit new heights.
1.2m journeys were taken by people who have gone to the Republic of Ireland in 2015 - 37% more than in 2014.
London's Heathrow was the most popular route from Dublin, followed by JFK in New York and Dubai.
George Best Belfast City Airport handled about 2.7m passengers in 2015 and Belfast International 4.4m.
Dublin Airport is the fastest growing major airport in Europe.
A spokesperson said the "significant increase" in passengers from Northern Ireland "was due in part to an expanded route network."
The airport serves 180 destinations in 40 countries.
Analysis by BBC NI's business correspondent, Julian O'Neill
Breaking the 1m barrier was inevitable - Dublin's recent growth has felt insatiable.
An improved motorway, Ireland's abolition of Air Passenger Duty and currency exchanges - until lately at least - have all fed its popularity.
But the biggest factor is route choice and flight frequency.
All told, Northern Ireland's airports offer only about one third of Dublin's total destinations.
It would be wrong to suggest Dublin is only capitalising on a dearth of long-haul options in the north.
Britain and continental Europe accounted for eight of the top ten routes for Northern Ireland passengers in 2015.