The group chief executive of Ryanair has said it is "likely" the airline will operate a number of weekly services from Waterford Airport, once an upgrade has been completed.
A €30m investment proposal to overhaul the facility was approved by Waterford City and County Council earlier this week.
The plan includes a runway extension and infrastructure upgrades aimed at providing for the return of commercial passenger services to the regional airport.
The project is fully funded through an unnamed US private investor.
Michael O'Leary said Ryanair would certainly look at operating some commercial flights into Waterford "if there's a jet runway" and "as long as it is free."
Speaking to RTÉ News, he said "It is likely, I would think, we might put in a London flight"."
"I think maybe you'd start off maybe two or three flights a week, Monday, Wednesday and Friday," Mr O'Leary said.
"We've said this to them in writing before. If you build a jet runway, we'll certainly look at maybe linking into London, two or three times a week, and we'll see where it goes from there," he added.
Asked if Ryanair would consider operating a daily service from Waterford, Mr O’Leary said it would be "highly unlikely."
I could be surprised, and I could be wrong, and maybe it might sustain a daily flight. I can't see us ever basing an aircraft in Waterford," the Ryanair boss added.
Waterford City and County Council said the airport development works, which it is estimated will cost in the region of €30m, are due to start early next year and will take around 12 months to complete.
In a statement, the Council said the investment will "pave the way for the return of scheduled passenger services by the end of 2027, with a target of handling upwards of 400,000 passengers annually within five years, as set out in the Airport Business Plan."
However, Michael O’Leary described the target as "pie in the sky" because he believes the regional airport "it is not a commercial proposition."
"It's not a commercial proposition, not because there is anything wrong with Waterford, it's just in the immediate catchment area of both Cork and Dublin," he said.
"The problem with Waterford is that it is less than a two-hour drive to Cork and less than a two-hour drive to Dublin," he said.
As a result it is "bang in the catchment area" of Cork Airport and Dublin Airport, which he said have "more route choices, more frequencies."
"Ultimately, Waterford is not a commercial proposition, and that's because there's nothing wrong with Waterford, it's just on the wrong side of the city and it's in the catchment area of Cork and Dublin," he stated.
Mr O’Leary said he believes Waterford "will be stuck with very small frequencies or very small schedules."
"I have never criticised Waterford Airport, by the way, we wish them well," he added.
"Ultimately, the challenge is we have too many airports in this country and the bigger ones cannibalise the smaller ones," he added.
This year marks the 40th anniversary of Ryanair’s first scheduled service between Ireland and Britain on a turbo prop plane from Waterford Airport to Gatwick Airport in London.
However, Michael O’Leary said any decision to return to Waterford Airport would not be made on nostalgia grounds.
"If it was from a nostalgic point of view, we'd all go back to driving donkeys," he said.
Emerald Airlines, the operator of the Aer Lingus Regional network, has welcomed the announcement of the redevelopment of Waterford Airport.
Asked if it would consider operating services at the airport, the airline said it is "continually exploring opportunities to expand our route network" as it moves into its next stage of growth.
In a statement, Emerald Airlines said it will "always consider new services that make strong commercial sense and align with our strategic goals."
