Gardai are investigating whether an unauthorised over-flight of the Border area by a British army aircraft took place last week. The Department of Foreign Affairs had sanctioned five over-flights which took place near the Louth/Armagh border on Thursday. The Garda Press Office confirmed an investigation was under way to find if a sixth, unauthorised flight took place in the north Co Louth region. The flights, in the Hackballscross area, were by British army fixed-wing aircraft.