What is a UFO?

There is much talk about UFOs sometimes. Is there anyway? If so what are they? Here are some questions we want to answer them briefly in this paper. An unidentified flying object or UFO is defined as any apparent object in the sky that can’t be identified and classified as an object or phenomenon already known. But the name is generally widely used to refer to the alleged or actual observations of alien ships. Today, the vast majority of observed UFOs are later identified as conventional objects or phenomena (such as aircraft, meteorological balloons, clouds). However, some of them can not be identified, either due to lack of evidence or due to the lack of conventional explanations, despite extensive evidence. Some people believe that the latest cases represent possible observations of alien spacecraft craft. The issue of past observations is difficult to explain otherwise than through the existence of other civilizations more advanced than ours. UFO events in the last thirty years are hard to analyze and classify, as we now have intelligent ships with special capabilities that can easily be confused with an alien ship.