Which of the following is included in the definition of Aircraft?

The definition of "Aircraft" specifically refers to any vehicle that is capable of flight, which includes both fixed-wing aircraft and helicopters. Both of these types of aircraft are designed to navigate through the air and achieve flight through various aerodynamic means. This encompasses a wide range of vehicles, from commercial airline jets to military aircraft and personal helicopters.

Regarding the other options, a boat does not qualify as an aircraft since it is designed for water travel and not for flying. An airport terminal, meanwhile, is a facility for facilitating air travel but is not an aircraft itself. Additionally, while a drone used for deliveries can be classified as an aircraft in a broader sense, the question appears to seek a clear and traditional definition of aircraft, which more directly aligns with fixed-wing aircraft and helicopters. Thus, the correct answer reflects the most standard interpretation of what constitutes an aircraft.