Guide; steer (5)
I believe the answer is:
pilot
I believe this is a double definition.
'guide' is the first definition.
(pilot can mean a navigator)
'steer' is the second definition.
(piloting is a kind of steering)
(Other definitions for pilot that I've seen before include "Flier or helmsman" , "Drive" , "This person can be found in a plane or a boat" , "may be up in the clouds" , "Captain of plane or boat" .)