It has emerged that the State has paid over €10m for foreign military overflights through its airspace over the last five years.
The figures were released to Labour TD Roisin Shortall, who said the vast bulk of the flights were likely to have been US military planes.
Under an international reciprocal agreement, military aircraft can be exempted from charges for using the airspace of other countries.
The Department of Transport reimburses the Irish Aviation Authority for the revenue foregone in this way.
Figures released to Ms Shortall, the Labour Party Transport Spokesperson, show these charges amounted to over €10m since 2000. Last year showed a huge increase on previous years with over €3.6m being paid.
Ms Shortall said that even though the Department of Transport had been unable to break down the overflights, it was almost certain that the vast majority were US military aircraft.
She called for an end to the policy of exempting these flights. She further claimed Ireland was getting a very bad deal as its position on the edge of Europe saw a large number of such overflights while very few Irish military aircraft used other countries' airspace.
In a separate reply, Transport Minister Martin Cullen told her that the number of US troops passing through Shannon in the first four months of this year was over 110,000, more than double the figure for the corresponding period in 2004.