Ryanair boss Michael O'Leary has said he does not believe that regional airports can survive without subsidies.
He was speaking just weeks after announcing his airline was pulling out of George Best Belfast City Airport at the end of this month due to an ongoing row over a runway extension.
Mr O'Leary said that Knock and Sligo airports would have a hard job keeping their public service obligation (PSO) contracts, which subsidise flights to Dublin, because they could no longer be justified.
Mr O'Leary has called for PSO contracts to be awarded to the regional airports and not the airlines.
Mr O'Leary was speaking in Tralee where he also met with local politicians to discuss Ryanair's ending of its PSO contract which provides three flights daily from Kerry to Dublin.
"The total quantity of PSO subsidies here is about â‚¬17m, of which we get â‚¬1.7m and Aer Arann gets the other â‚¬15.3m," he said.
"It would be cheaper for us as taxpayers to provide a fleet of limos outside the door of Knock Airport and drive them to Dublin.
"I would like to continue three flights a day. But I'm not going to subsidise Noel Dempsey or the Dublin Airport Authority to the tune of â‚¬660,000 a year to do it."