Complex sentence: But he had a passenger, one Major Helmouth Rienburger, who was responsible for organising the supplying of Fliegerdivision 7 the unit that was to land paratroopers behind the Belgian lines on the day of the coming attack.
Split into simpler sentences: But he had a passenger, one Major Helmuth Reinberger, who was responsible for organising the supplying of 7. Fliegerdivision, the unit that was to land paratroopers behind the Belgian lines on the day of the coming attack.