Top amongst German aircraft (6)
I believe the answer is:
glider
'aircraft' is the definition.
(glider is a kind of aircraft)
'top amongst german' is the wordplay.
'top' becomes 'lid' (lid is a kind of top).
'amongst' is an insertion indicator (I've seen this in other clues).
'german' becomes 'ger' (abbreviation).
'lid' going within 'ger' is 'GLIDER'.
(Other definitions for glider that I've seen before include "Plane without an engine" , "Engineless plane" , "quiet flier" , "taking flight?" , "Powerless aircraft" .)