The most common and most likely answer to this crossword clue is the 6 letter word OUSELS
I've seen this crossword clue in The Daily Telegraph
O
U
S
E
L
S
Buddy explains!
The straight part
We know that "fliers" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fliers = ousels.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 OUSELS mean?
OUSELS noun- The Eurasian blackbird, Turdus merula.
- The water ouzel, an aquatic perching bird, Cinclus mexicanus.