Flying machine managed to cross river (5)
I believe the answer is:
drone
'flying machine' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'managed to cross river' is the wordplay.
'managed' becomes 'done' (I've seen this before).
'to cross' is an insertion indicator (some letters cross or go round others).
'river' becomes 'r' (abbreviation).
'done' placed around 'r' is 'DRONE'.
Can you help me to learn more?
(Other definitions for drone that I've seen before include "Idler like male bee" , "Bee, speak tediously" , "fine lady?" , "Continuous sound; bee" , "Unmanned aircraft" .)