Concern over Concorde concentrated the minds of the government 30 years ago. Ministers were worried about the fallout on the tourism trade from the still-to-fly Anglo-French supersonic aircraft.
The Concorde did not become airborne until March 1969, but anxieties were being expressed about the project in Dublin a year earlier.
One document highlighted fears that the Concorde "overpressure" area could stretch for 60 miles in one direction and 27 miles in the other.
Believing "the relative tranquillity" of Ireland was a major factor in attracting tourists, some ministers felt Concorde's sonic boom would have damaging consequences for the holiday industry, and urged the drafting of legislation to ban the noise.