Extraterrestrial vessel and Unidentified flying object

Unidentified flying object and extraterrestrial vessel are semantically related. in spaceship topic. In some cases you can use "Unidentified flying object" instead a noun phrase "Extraterrestrial vessel".

Unidentified flying object noun - An (apparently) flying object whose nature is unknown; especially those considered to have extraterrestrial origins.

Extraterrestrial vessel and unidentified flying object are semantically related. You can use "Extraterrestrial vessel" instead a noun phrase "Unidentified flying object".