The Schweinfurt task forces followed the same route as the Regensburg force. Because of the delayed start of the mission, eight squadrons of RAF Spitfire fighters (96 aircraft) from 11 Group and 83 Group had been added to escort the Schweinfurt force as far as Antwerp, where P-47s would take over and escort it to Eupen. The field order for the mission specified that the B-17s would fly at altitudes between 23,000 and 26,500 feet (7,000-8,000 m), but approaching the coast of the Netherlands at 13:30, it was confronted with developing cloud masses not present earlier in the day. The commander of the first task force estimated that the bombers would not be able to climb over the clouds and elected to fly under them at 17,000 feet (5,000 m), increasing the vulnerability of the bombers to fighter attacks.