They were around 100 miles off the coast of San Diego in separate F/A-18F Super Hornets when they spotted the object in 2004. Some of what they saw has now been released by the Pentagon. The object was first spotted by the USS Princeton which wanted to know if the mysterious aircraft was carrying weapons. A mysterious object that could fly at incredible speeds was spotted by two U.S. Navymen (Picture: US Department of Defence) They tracked it for a couple of weeks before going up to have a look at it. Fravor said the objects appeared at 80,000ft then sped towards the sea, stopping at 20,000ft where they would then hover before disappearing off the radar or shooting into the sky.