flying saucer
Some crop circles have been attributed to paranormal activity, natural phenomena, or unidentified flying objects.
In the west of the US there have been many reported cases of unidentified flying objects.
A group of scientists has called for the serious scientific study of unidentified flying objects.
SMART Vocabulary: related words and phrases Space travel
airlock
astronaut
astronautics
autopilot
biosatellite
blast
capsule
cosmonaut
escape velocity
EVA
flyby
launcher
rocket science
rocket scientist
space capsule
space probe
space shuttle
space tourism
space tourist
spacewalk
You can also find related words, phrases, and synonyms in the topics:
Air travel: aviation