The most common and most likely answer to this crossword clue is the 8 letter word AIRBORNE
I've seen this crossword clue in The Guardian
A
I
R
B
O
R
N
E
More clues leading to the result AIRBORNE
- A robin, er, surprisingly, flying
- Bearing north-east to save British soldiers – so paras?
- Brought to life, submerged in river or up in the sky?
- Announces scion delivered in travelling up
- Tune carried aloft
- Flying first class, queen goes to island, briefly
- Character suffered in flight
- Iron brace fixed without carbon, like a hang-glider must be
- Vocal person likely to succeed, natural and upwardly mobile
- ‘Up Up And Away‘ tune endured
Buddy explains!

The straight part
We know that "Flying" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case flying = airborne.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 AIRBORNE mean?
AIRBORNE noun- Military infantry intended to be transported by air and delivered to the battlefield by parachute or helicopter.
- In or carried by the air.
- In flight.
- Fitted to an aircraft.
- Transported by air in an aircraft.