The 1952 Air Navigation Order sets out specific stipulations by which foreign military aircraft are permitted to overfly and land in the State. It is in accordance with these stipulations and on the basis of advance clearance requests that US military aircraft have been granted permission by successive Ministers for Foreign Affairs to refuel at Shannon Airport over a period of decades. Arrangements concerning US overflights date from 1959 and were put in place by then Minister for External Affairs, Frank Aiken. Reflecting security considerations which prevailed during the Cold War years and which have since been upheld by successive Governments, these arrangements require that such overflights be unarmed. Moreover, in the vast majority of cases, they relate to ordinary supplies and equipment. The US Embassy supplies post hoc statistics of the overflights on a monthly basis.