Leading hotel on a budget finally getting suitable cover (3,3)
'suitable cover' is the definition.
(formal covering for one's head)
'leading hotel on a budget finally' is the wordplay.
'leading' becomes 'top' (both can mean first-class).
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'on' is a charade indicator (letters next to each other).
'finally' indicates one should take the final letters.
The final letter of 'budget' is 't'.
'getting' is the link.
(Other definitions for top hat that I've seen before include "1935 Fred Astaire/Ginger Rogers film", "Astaire musical", "It's seen with tails", "Formal headgear for man", "Film with Astaire and Rogers".)