What are the types of braking systems that can be applied in flight?

The correct answer addresses the various braking systems utilized during flight, particularly during landing. Ground spoilers are devices that extend from the wing surfaces to disrupt airflow, reducing lift and increasing drag, which aids in decelerating the aircraft. Disc brakes are commonly found on the aircraft's landing gear, providing a friction surface that slows down the aircraft upon touchdown. Reverse thrusters, also known as thrust reversers, redirect engine thrust forward to aid in deceleration after landing by effectively increasing the aircraft's braking capability.

In contrast, while air brakes and wing flaps are crucial components for managing aerodynamics and lift during flight, they are not classified strictly as braking systems in the context of slowing down an aircraft upon landing. Additionally, a drag chute, while effective for rapid deceleration, is not typically categorized with ground spoilers and disc brakes, as it is more of an auxiliary device rather than an integrated part of the braking system. Finally, ailerons and elevator controls are essential for maneuvering the aircraft but do not directly contribute to the braking process.