Cork and Dublin Airports face a loss of traffic if the Government does not lower airport charges.
That's according to Ryanair chief executive Eddie Wilson, who says the Government has to go above and beyond other countries.
He told Newstalk Breakfast: "We're now into the recovery phase and... because of airline bankruptcies and reductions, there's going to be less airline seats in Europe next year by somewhere in the order of about 20%."
He was speaking after the Irish carrier announced eight new routes from Shannon Airport, as well as basing an additional aircraft there.
The expansion will see Ryanair operating 16 routes from Shannon this summer and 18 routes for winter.
Mr Wilson says Shannon "put in a competitive, long-term deal for us so that we can actually grow".
But he says Dublin and Cork may see themselves standing still.
"What you have in Dublin and Cork is - the daa essentially have their hands tied - because they have their own funding problems at the moment.
"It's really a Government issue of infrastructure here - and if you're going to restore traffic, you have to incentivise airlines.
"Ireland, as an island nation, needs to do something over and above the Germany's and the France's and Netherlands who have got other alternatives to move around by rail."
He says a daa scheme to help airlines runs out in the middle of next year.
"They have a scheme in, but unfortunately it runs out on the 30th of June - in the middle of the summer - next year.
"The deals that we've done elsewhere are longer-term ones so that we can plan.
"The daa have their own funding difficulties - like us, we've had no passengers and they're the same passengers that go through the airport
"This is an issue of national infrastructure".
He says the Government needs to lower, or scrap, airport charges for a period.
"One of the worst things that's probably going to come out of this, is that if you listen to the most bullish economic [commentators] ... if they're right, we could end up with an economic boom in Europe in the next number of years - and we'll have less connectivity on and off this island".