Disreputable (but attractive) British fliers and swimmers (7)
I believe the answer is:
raffish
'disreputable but attractive' is the definition.
(I've seen this before)
'british fliers and swimmers' is the wordplay.
'british fliers' becomes 'RAF' (Royal Air Force).
'and' means one lot of letters go next to another.
'swimmers' becomes 'fish'.
'raf'+'fish'='RAFFISH'
(Other definitions for raffish that I've seen before include "unconventional" , "Dissolute" , "Rakish" , "like British airmen?" , "Tawdry" .)