Warning seen by abandoned Soviet group of planes? (6)
I believe the answer is:
forest
'group of planes?' is the definition.
'forest' can be an answer for 'group' (forest is a kind of group). I am not certain of the 'of planes?' bit.
'warning seen by abandoned soviet' is the wordplay.
'warning' becomes 'fore' (I've seen this in other clues).
'seen by abandoned soviet' becomes 'st' (I can't explain this - if you can you should believe this answer much more).
'fore'+'st'='FOREST'
Can you help me to learn more?
(Other definitions for forest that I've seen before include "large area covered with trees" , "Large area of woodland" , "that has branches everywhere" , "New, Epping or Sherwood" , "Sherwood or Pine, say" .)