Ryanair has estimated that Dublin Airport traffic numbers will fall by about 500,000 passengers if the airline goes ahead with a threat to reduce the number of flights it operates from the airport. The airline, which says it currently pays State airport operator Aer Rianta £2.15 for every arriving and departing passenger, insists it will reduce its dependency on the airport if a deal with Aer Rianta to avoid rises in landing fees due to the ending of intra-EU duty free cannot be reached.