The most common and most likely answer to this crossword clue is the 2 plus 2 plus 3 plus 3 letter word UP IN THE AIR
I've seen this crossword clue in The Times
U
P
I
N
T
H
E
A
I
R
More clues leading to the result UP IN THE AIR
- Undecided where one might throw a ball?
- Undecided where rocket should go
- Uncertain and without energy, you fasten time locks
- Sounds like you try nursing a beer to keep one excited
- Travelling in Boeing? Not yet decided
- Universal pub tipple – try imbibing one – undecided?
- 9? Undecided
- Where pilots will fly is not yet decided
- Where are the clouds? Not sure
- Still unsure where to look for helicopter, for example?
Buddy explains!

The straight part
We know that "Uncertain" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case uncertain = up in the air.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.