In a brazen heist right out of the movies, thieves drove onto Belgium's airport tarmac and stole more than $50 million of diamonds from a plane without firing a single shot. It took them fewer than five minutes to cut through an airport fence Monday night, drive up to a Helvetic jet in cars with flashing lights, hold up the pilot and security officials on the plane, and take 120 packages of rough and cut stones, according to the Belgium prosecutor's office. The men carried submachine guns, were dressed in police uniforms and camouflage masks. "It was a well prepared operation. Robbers knew exactly when Brinks diamond and jewellery services truck would load" at 8:05 p.m., Ine Vanwymersch, told ABCNews.com. Vanwymersch said the thieves "forced open the fence between two construction sites," allowing them onto the tarmac. She said they ordered…