force, they don t use the term area 51 to describe the live tire training range, large live fire training range, largest in united states, one of many reasons that air force officials don t want people to trespass on the base, they are worried some might be killed. saying quote: military spent 22 million wildollars to re search ufo s lt month navy briefed several senators on capitol hill about ufo encounters like this one. from a navy f-18 training mission 4 years ago off of the east coast of the united states, an unidentified aerial phenomenon.