The most common and most likely answer to this crossword clue is the 9 letter word UNDERSHOT
I've seen this crossword clue in The Daily Telegraph
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More clues leading to the result UNDERSHOT
Buddy explains!
The straight part
We know that "Was inadequate as an air gunner/fell short as a pilot" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case was inadequate as an air gunner/fell short as a pilot = undershot.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 UNDERSHOT mean?
UNDERSHOT verb- To shoot not far enough or not well enough.
- To not go far enough when trying to reach a goal.
- (by extension) To underestimate.
- An undershot water wheel.
- (of a water wheel) Powered by water flowing from below.
- Having the lower incisor teeth projecting beyond the upper ones, as in the bulldog.