A bit disorientated, RAF chap covers miles (8)
I believe the answer is:
fragment
'a bit' is the definition.
(thesaurus)
'disorientated raf chap covers miles' is the wordplay.
'disorientated' is an anagram indicator.
'chap' becomes 'gent' (I've seen this in other clues**).
'covers' indicates putting letters inside.
'miles' becomes 'm' (common abbreviation).
'gent' enclosing 'm' is 'gment'.
'raf' with letters rearranged gives 'fra'.
'fra'+'gment'='FRAGMENT'
(Other definitions for fragment that I've seen before include "Small piece" , "Broken-off piece" , "Incomplete part" , "Small portion" , "Come to pieces" .)