An Israel Aero Space Industries (IAI) Heron 1 unmanned aerial vehicle (UAV) flies over the airbase in the central Swiss town of Emmen September 20, 2012. The Swiss air force is currently evaluating the reconnaissance drone aircrafts of two Israeli companies to replace its existing systems. Picture taken on September 20. REUTERS/Arnd Wiegmann (SWITZERLAND - Tags: MILITARY TRANSPORT BUSINESS)