Howdo Chappers
I'm afraid I didn't see the show but have witnessed the helicoptering-in of stone on the North York Moors.
The stone used there was recycled from the floors of redundant/demolished mills and factories. These foot-thick stone flags are just the job when it comes to repairing footpaths and should pretty much last forever. They tend to be used where there is severe footpath erosion.

The use of a helicopter is ideal, helicopters can handle heavy payloads delivered with pin point accuracy and leave no trace on the landscape. The alternative is multiple journeys by all-terrain, heavy vehicles into areas that have probably already suffered from footpath erosion, essentially adding to the problem.

Helicopters are a cost efficient, fuel and time efficient method of delivering heavy loads into sensetive areas. If North Yorkshire is anything to go by a lot of the labour used to repair and maintain these pathways is provided by volunteers who walk into the area once the loads have been delivered. Again, cost, fuel and time efficient with minimal impact on the landscape.

cheers
fitz