The most common and most likely answer to this crossword clue is the 7 letter word FRISBEE
I've seen this crossword clue in The Times
F
R
I
S
B
E
E
Buddy explains!

The straight part
We know that "Flying saucer?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case flying saucer? = frisbee.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does FRISBEE mean?
FRISBEE noun- A disk-shaped gliding toy.
- The sport involving Frisbees.
- To throw something in the manner of a Frisbee.