The most common and most likely answer to this crossword clue is the 8 letter word TRIPLANE
I've seen this crossword clue in The Daily Telegraph
T
R
I
P
L
A
N
E
Buddy explains!

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 TRIPLANE mean?
TRIPLANE noun- An airplane that has three pairs of wings, one above the others