Suspected DMZ 'helicopters' lead to friendly-fire strike on HMAS Hobart
On 16-17 June 1968, U.S. Air Force jets whose pilots took the radar returns of allied ships for enemy helicopters attacked several ships near the Vietnam DMZ, hitting HMAS Hobart and killing two sailors. In 1973 USAF chief Gen. George Brown described the episode as a series of UFO sightings.