Which airliner utilizes composite materials for the majority of its primary structures?

The airliner that utilizes composite materials for the majority of its primary structures is the A-320. The Airbus A-320 series features a significant amount of composite materials, particularly in its wings and fuselage. The use of composites in its construction allows for reduced weight, which improves fuel efficiency and overall performance. The A-320 was one of the first commercial airliners to incorporate such advanced materials extensively, making it a leader in modern aircraft design and engineering.

In comparison, while the U-2 and SR-71 experienced advancements in materials, they are military aircraft rather than commercial airliners, and their primary structures are not primarily composed of composite materials. The Beechcraft Twin Bonanza is a general aviation aircraft and does not utilize composites to the extent found in the A-320. Similarly, the Boeing 727, which was developed earlier, relies heavily on traditional aluminum structures, and thus does not incorporate composite materials for the majority of its primary structures.