Which characteristic is essential for the operational performance of the Boeing 787?

The essential characteristic for the operational performance of the Boeing 787 is its use of lightweight materials. The aircraft primarily utilizes composite materials, such as carbon fiber reinforced polymer, which significantly reduces its overall weight compared to traditional aluminum structures. This reduction in weight leads to enhanced fuel efficiency, allowing the 787 to achieve greater range and lower operating costs.

By being lighter, the aircraft can carry more payload while using less fuel, which is crucial for airlines focused on economic efficiency and environmental impact. The design philosophy of incorporating these materials was a significant innovation, contributing to the 787's reputation as one of the most fuel-efficient and performance-oriented aircraft in its class.

While features like two engines, large cockpit displays, and automatic landing systems are important, they do not have the same direct impact on operational performance related to fuel economy and range as the lightweight materials do.