Former Aer Lingus chief executive Mr Willie Walsh has called for the immediate abolition of the Shannon stopover rule, which, he said, was harming the airline business and resulting in higher fares at Dublin Airport.
Mr Walsh said the rule was "restrictive", "not in the national interest" and was stopping new carriers from entering the Irish market.
Mr Walsh said Aer Lingus would not have announced plans to end its Baltimore/Washington service if the Shannon stopover had been abolished.
A few months ago Aer Lingus announced it was ending its services to the airport from May 9th this year.
Currently, under a bilateral agreement between the Republic and the US, half of all flights between Ireland and the US must allow passengers to disembark at Shannon.
Mr Walsh told a conference on aviation regulation, hosted by the Institute of European Affairs, there was a "significant imbalance" in demand between Shannon and Dublin airports.
Using Aer Lingus figures from 2001, he said the company's route from Shannon to JFK in New York made losses in 10 months of that year; whereas Dublin direct to JFK was profitable in 10 months of that year. Shannon was one the reasons Aer Lingus ended up "on its knees" in 2001.
He said if the stopover rule was ended "you could significantly lower fares out of Dublin".
He said there was no need for a "transitional arrangement", and the stopover should be ended immediately.
Asked whether a five-year transition should be agreed before the stopover was abolished, Mr Walsh disagreed.
"Five years is a hell of a long time in the airline industry."
Speaking at the same event, a senior US official said the US was willing to end the stopover rule but only if the Irish Government wanted to take such a step.
Mr John Byerly, deputy assistant secretary for transportation affairs at the State Department, said the current agreement also prevented Irish carriers from serving certain airports.
"As many of you are aware, the United States was and is willing to phase out restrictions over a reasonably short period if this is Ireland's desire.
"From a transatlantic perspective, Ireland today lacks the unlimited market access to the United States that carriers from most other EU countries enjoy. In the absence of open skies, Aer Lingus cannot offer the range of services to which Air France, Lufthansa, Alitalia, KLM, SAS, LOT and others are entitled under their bilateral agreements with the United States."
He said while he understood the desire of airlines like Aer Lingus to fly into more US cities, he was not convinced European airlines wanted to compete in the domestic US market. The right to operate in the US internal market was known as "cabotage".
"Honestly, is cabotage the market access that Aer Lingus and British Airways and Lufthansa and SAS really want?
"The right to operate their own aircraft head-to-head with Southwest, JetBlue, Valujet and a dozen other US carriers in their established home markets inside the United States? I just don't think so."