The most common and most likely answer to this crossword clue is the 7 letter word REFLATE
I've seen this crossword clue in The Times
R
E
F
L
A
T
E
More clues leading to the result REFLATE
- Game official and others sent back balloon again
- Get pumped up about female behind
- Sports official overdue? Blow up again!
- Reason for game being delayed causes blow-up again
- Boost cause of delayed kick-off?
- Judge delayed raise expenditure
- Chief of finance checking report — it’s a way to improve the economy
Buddy explains!

The straight part
We know that "balloon again" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case balloon again = reflate.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 REFLATE mean?
REFLATE verb- To reinflate, to inflate again.
- To restore the general level of prices to a previous or desirable level.