UFO are mostly military planes that look a little different or weather ballons or even if it's something else they are still "unidentified". an Alien is one who originated and came from outer space ,I don't think you can say for sure until humans have enough resources to actually explore space.
humans have enough resources but they are spent on bankers hookers and blow, not space exploration
"We come for piece, and while we're here learn us about your bankers and blow."