BAE Systems Electronics, Intelligence & Support is next to Rochester Airport and the M2, where they make helmet mounted displays and head-up displays; it was GEC Avionics, previously Marconi Avionics and Elliott Flight Automation, and Kent's biggest employer in the 1980s; the display technology originated from acquiring Cintel in 1963; the site was a Shorts factory in the war, and built many Short Sunderlands. The Royal Engineers and the Royal School of Military Engineering are based in Chatham at Brompton Barracks. London Thamesport is on the Isle of Grain.