For reasons as yet unknown, the tractor crashed through a noise protection wall and fell several metres down a grassy slope before coming to a stop on the top of a wall overlooking the A8 in Sarnen, police said.
Called to the scene, firemen first had to ensure the tractor wouldn't fall on to the road before they were able to extract the driver from his predicament.
Injured, he was airlifted to hospital by helicopter rescue service Rega.
The A8 was shut in both directions for three hours while the tractor was removed with a crane.
The damage is estimated at several thousand francs, said police.