Pennant, perhaps right to be carried by older ship (8)
I believe the answer is:
streamer
'pennant perhaps' is the definition.
(type of flag or streamer)
'right to be carried by older ship' is the wordplay.
'right' becomes 'r' (common abbreviation).
'to be carried by' indicates putting letters inside.
'older ship' becomes 'steamer' (steamship).
'r' inserted into 'steamer' is 'STREAMER'.
(Other definitions for streamer that I've seen before include "Long flag, tapering perhaps" , "Item of bunting" , "Bit of bunting" , "that hangs about now?" , "Arrest me carrying floating ribbon" .)