They are the most advanced fighter jets in the world, capable of flying at 1,200mph while staying virtually invisible to enemy radar, equipped with unrivalled surveillance capabilities and a devastating array of missiles.
Every year roughly 150 new state-of-the-art planes, which have quickly become the backbone of modern Western air forces, rise from a base in Fort Worth, Texas, for delivery around the world.
But serious doubts about the programme that brings billions of dollars into the US have emerged in recent weeks due to one burning question – can allies rely on America any more?
