Krikkiter,
OK we can use your example very well here. In the official definitions, UFOs are separated from other objects by appearance and performance characteristics that do not match known manmade or natural objects or phenomena. So even if a distant light or unidentified object were spotted that could have been explained as an aircraft, it was not to be reported as a UFO.
Similarly, popular modern usage and definitions define UFOs as extraterrestrial spacecraft, flying saucers or some other alien craft. At the very least, the common denominator is that they are something extraordinary to the observer that seems to defy explanation.
Therefore if you believed the object you saw could have been explained as a satellite, then it was not a UFO. So saying "I saw a UFO" with respect to that object would not be correct usage. However saying, "I saw something once that could have been a satellite." would be OK.
Now if that light that had seemed like a satellite had suddenly stopped and then instantly accellerated down to hover in a field across from you and looked like some sort of alien craft, then darted away over the horizon, it would be perectly acceptable usage to say, "I saw a UFO", and everyone would know you weren't just talking about some "unidentifed" but otherwise ordinary object.
In either case you might be inclined to fill out a UFO report. This is where the context of usage has its second application. The object you actually saw would become the subject of a UFO report, but that doesn't mean it was an actual UFO. So it would be correct to ask with respect to the UFO report, "What is the object in this UFO report?" But it would not be correct usage to ask, "What is the UFO in this report?"
Because the semantics issue in ufology is not well understood it is common to see many incorrect usages, even among ufologists. Critics and skeptics also tend to capitalize on this to spread their propoganda, usually by pontificating about the relevance of the word "unidentified" as part of the origin of the word UFO, and failing to acknowledge that the word origin and the word's definition and meaning are significantly different. In the case of the critics here, you see them capitalize on it by misrepresenting my position in the form of gross oversimplification. They are well aware of issue and it has been discussed here at length, so they can't use the excuse that they don't know. It's just willful ignornace and deception.