IRISH Rail is planning a new line to allow intercity trains to travel direct to Dublin airport from Cork, Galway and Belfast.
Chief executive David Franks outlined his vision for the new route in an interview with the Irish Independent.
The company says the line could cost as little as €300m, but would open the entire rail network to air passengers and boost tourism.
The company could also run services from the regions direct to the airport - reducing the need for passengers to use expensive airport parking.
But the plan would risk pulling even more passengers towards Dublin and away from regional airports.
The loss of routes and declining passenger numbers at Cork Airport has already raised serious concerns about its future.
Traffic through Cork last year fell 3.8pc at a time when Shannon's figures rose 18.7pc and Dublin by 6.5pc.
Mr Franks believes that Irish Rail must work to connect with Dublin Airport for the first time.
"One of the biggest contributions we can make to the economy is moving people over long distances and into city centres fast," the chief executive told the Irish Independent.
"My vision is more a Manchester Airport connection where you can go all over the country using diesel trains.
"You could gain access to Cork, Galway or Belfast. We think it could be done for about €300m, but that's very rough and ready."
Irish Rail might run intercity services direct to the airport, or else link the airport and city by DART before switching to intercity trains.
The ambitious plan would involve building a spur line to the airport from Clongriffin.
This is already being considered by the Department of Transport, in the context of developing a new public transport option for north Dublin.
But the second part would involve a second line from the airport to Swords, before connecting back onto the main Dublin-Belfast line, which would also service commuters from Drogheda and Dundalk.
It would also serve commuters in Swords, north Dublin and Louth. Trains could run every 15 minutes into the city, with the trip taking 20 minutes. As the line is underneath the flight path, no property would be affected.
Irish Rail believes it could be built in less than five years, and carry three million airport passengers. Research suggests that 24pc of people travelling through airports use a rail link.
The scheme would also be enhanced if the proposed DART Underground project goes ahead, which will link the main lines between Heuston Station and Connolly Station.
The journey from Cork to Dublin Airport, via the Phoenix Park Tunnel expected to open next year, would take around three hours and 30 minutes.
With the DART Underground, the journey would be around three hours. However the plan is not dependent on this €4bn project going ahead.