Which class of kingdom Animalia is characterized by the presence of feathers and adaptations for flight?

The class of the kingdom Animalia that is characterized by the presence of feathers and adaptations for flight is Aves, which encompasses all birds. Feathers are a unique feature of Aves, providing not only insulation and waterproofing but also enabling the aerodynamic properties necessary for flight. These adaptations include a lightweight skeletal structure, powerful muscles for flight, and modifications in their respiratory and circulatory systems that support high metabolic demands during flight.

Mammalia, while a diverse group with adaptations for various environments, lacks feathers and the specific adaptations associated with flight as seen in birds. Reptilia includes animals such as snakes, lizards, and turtles, which do not have feathers and have distinctly different adaptations, primarily for terrestrial life or swimming, rather than flight. Insecta, though it includes many flying species, does not fall under the same classification as vertebrates and is characterized by a different body structure and life cycle.

Thus, Aves stands out as the only class that meets the criteria of having feathers and flight adaptations, making it the correct choice.