The most common and most likely answer to this crossword clue is the 6 letter word AIRIER
I've seen this crossword clue in The Daily Telegraph
A
I
R
I
E
R
Buddy explains!

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 AIRIER mean?
AIRIER adjective- Consisting of air.
- Relating or belonging to air; high in air; aerial.
- Open to a free current of air; exposed to the air; breezy.
- Resembling air; thin; unsubstantial; not material; airlike.
- Relating to the spirit or soul; delicate; graceful.
- Not based on reality; having no solid foundation
- Light-hearted; vivacious
- Having an affected manner; being in the habit of putting on airs; affectedly grand.
- Having the light and aerial tints true to nature.