The most common and most likely answer to this crossword clue is the 7 letter word BIPLANE
I've seen this crossword clue in The Times
B
I
P
L
A
N
E
More clues leading to the result BIPLANE
Buddy explains!

The straight part
We know that "aircraft" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case aircraft = biplane.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 BIPLANE mean?
BIPLANE noun- An airplane that has two main wings, one above the other and supported by struts
- Having, or consisting of, two superposed planes, aerocurves, etc.