The fastest route is through the air.

 Helicopters are used for many different types of missions, including assault, search and destroy, scouting, transport and resupply. The Army also utilizes Unmanned Aerial Vehicles (UAVs) to perform strikes and reconnaissance without risking manpower.

http://www.goarmy.com/about/army-vehicles-and-equipment/army-helicopters-and-uavs.html