By Alastair Leithead BBC News, New Mexico
Unmanned aircraft are the new cornerstone of modern military operations, and both American and British crews are learning to fly them at a New Mexico Air Force base. There, they must tackle the practical questions of what it means to wage war from afar.
America and its allies are fighting wars around the world from computer screens in the deserts of Nevada and New Mexico.
Drones – officially known as remotely piloted aircraft – have become a major part of modern warfare.
These unmanned aircraft have the ability to fly above contentious areas, taking and relaying surveillance photos. The most controversial drones have the ability to launch an attack via onboard weapons.
America operates thousands of drones, with the bigger, more sophisticated versions controlled from bases in the US.