Complex sentence: Both Heinkel and Messerschmitt developed designs to meet the requirements and by 1959 the two companies had created a joint venture company, called EWR, to build the VJ 101 C, which combined the characteristics of the Heinkel and Messerschmitt designs.
Split into simpler sentences: Both Heinkel and Messerschmitt developed designs to meet the requirements. By 1959 the two companies had created a joint venture company, called EWR, to build the VJ 101 C, which combined the characteristics of the Heinkel and Messerschmitt designs.