Travel free, heading for Estonia (4)
I believe the answer is:
ride
'travel' is the definition.
(riding is a kind of travelling)
'free heading for estonia' is the wordplay.
'free' becomes 'rid' ('rid' can be a synonym of 'free'**).
'heading for' says to take the initial letters.
The first letter of 'estonia' is 'e'.
'rid'+'e'='RIDE'
(Other definitions for ride that I've seen before include "To control" , "Sit on (a horse/vehicle)" , "Travel, by horse say" , "spin > lift > pedal" , "Fairground entertainment" .)