How are swifts and swallows different?

Swifts and swallows are both small, aerial birds, but they belong to different families and have distinct physical traits. Swifts typically have longer wings and a more streamlined body, which allows for faster flight, while swallows have shorter wings and a more rounded body. Additionally, swifts are known for their unique ability to spend most of their lives in the air, even sleeping while flying, whereas swallows are more commonly seen perched and are known for their distinctive forked tails. Their nesting habits also differ, with swifts usually nesting in crevices or under eaves, while swallows build mud nests.