Planes kept here hover by a river (6)
I believe the answer is:
hangar
'planes kept here' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'hover by a river' is the wordplay.
'hover' becomes 'hang' (I've seen this before).
'by' means one lot of letters go next to another.
'river' becomes 'r' (abbreviation for river).
'hang'+'a'+'r'='HANGAR'
Can you help me to learn more?
(Other definitions for hangar that I've seen before include "Airfield building" , "storage location" , "Large shed to house aircraft" , "Airport shed" , "Large structure for housing aircraft" .)