What does the cryptic crossword clue "Where a flyer may go for a walk in London (8)" mean?

The definition is "Where a flyer may go / a walk in London". The wordplay uses a double definition. Double definition The answer is BIRDCAGE.

Where a flyer may go for a walk in London (8)

Times Cryptic #28963 | 13 Across | 2024-07-08 flower