In early 1948, with the upcoming end of the British Mandate for Palestine and the looming confrontation with Israel's Arab neighbors, the leadership of the Yishuv embarked on a worldwide effort to purchase weapons. Despite an American arms embargo, Israeli acquisition agents managed to purchase four commercial B-17 Flying Fortresses in the US. Two were demilitarised and modified for freighter use by Aerodex Inc. of Miami, then sold unknowingly to a front company that said they would be used in the Caribbean. The first two departed the city on June 12, followed a day later by a third, and made their way first to Puerto Rico and then across the Atlantic via the Azores to Žatec, Czechoslovakia, where they arrived on June 14. By June 16 the story had made it to the press and the fourth plane, whose crew only barely managed to elude the FBI, was impounded in the Azores by Portuguese authorities. At Žatec the three B-17s, missing bomb shackles and sights, oxygen systems and defensive weapons, were militarized and the squadron that was to operate them, at the time referred to as the "Hammers Program", first took shape. Ray Kurtz, a former B-17 navigator with 31 missions over Europe, was assigned command of the squadron, staffed by an international crew of World War II veterans who volunteered to fight for Israel. Robert Luttrell, a sailor by trade, flying as a bombardier, recalled that for each mission the B-17s were given new markings and their armament was altered to lead the enemy to believe Israel possessed an entire squadron of the type.