Complex sentence: At this time Cliff had 6 planes in the airmail service to Cleveland and expanded his growing list of aircraft with a Ford tri-motor, another Fairchild FC-2, five New Standard D-27, and seven Waco 9's as payment for a storage charge.
Split into simpler sentences: At this time Cliff had 6 planes in the airmail service to Cleveland. Cliff expanded his growing list of aircraft with a Ford tri-motor, another Fairchild FC-2, five New Standard D-27, and seven Waco 9's as payment for a storage charge.