Couples head off with speed in flying area (8)
I believe the answer is:
airspace
'couples head off with speed' is the definition.
I can't tell whether this definition defines the answer.
'flying area' is the wordplay.
'flying' becomes 'air' (similar in meaning).
'area' becomes 'space' (space is a kind of area).
'air'+'space'='AIRSPACE'
'in' is the link.
Can you help me to learn more?
(Other definitions for airspace that I've seen before include "What pilot goes through" , "Here planes fly" , "Atmosphere over (area of) earth" .)