Complex sentence: The combination of increased capacity and range offered by the 767-300ER was particularly attractive to both new and existing 767 operators, making it the most successful version of the aircraft, with more orders for this type than all other variants combined.
Split into simpler sentences: The combination of increased capacity and range offered by the 767-300ER has been particularly attractive to both new and existing 767 operators. It is the most successful version of the aircraft, with more orders placed than all other variants combined.