The most common and most likely answer to this crossword clue is the 6 plus 4 letter word GROUND CREW
G
R
O
U
N
D
C
R
E
W
More clues leading to the result GROUND CREW
- Those labouring on jumbo maybe bought drinks and boasted after finally finishing
- . Airport staff dreadfully rude? Wrong, when keeping cool head
- About hundred in expanded team at airport
- Airport staff increased to conceal portly contralto
- Aircraft mechanics originally urged Crown to be plentiful reviewing pay
- Mechanics, having sufficient reason, cried out in triumph
- 2 team expanded to restrict heat and carbon
- Not the high-fliers among Ronald Reagan or JFK’s staff?
Buddy explains!

The straight part
We know that "Not the high-fliers" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not the high-fliers = ground crew.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.