What is the primary purpose of landing gear in an aircraft?

The primary purpose of landing gear in an aircraft is to support the aircraft during takeoff, landing, and while on the ground. This functional requirement is critical as landing gear must be designed to withstand the significant loads encountered during these phases of flight, ensuring the aircraft remains stable and safely supports its weight when not airborne.

Landing gear also provides the necessary interface with the runway or ground surface, allowing for safe ground operations such as taxiing and parking. Its design takes into account the need for shock absorption during landing, as well as the capability to facilitate smooth transitions onto and off of the runway. This makes it an essential component of an aircraft's structure and operational integrity, as it allows the aircraft to efficiently interact with its environment once it leaves the airspace.

In contrast, while aerodynamic performance, fuel efficiency, and altitude control are important considerations in aircraft design and operation, they are not the primary functions of the landing gear itself. These aspects are addressed by other systems and components within the aircraft.