Most seabirds spend most of their time in the air, except when nesting.
Polar bears spend most of their time on land.
they live on air because then they can see their predators around
Enormous animals have enormous lungs which can hold enormous amounts of air for an enormously long time.
The wings of a bird help the bird float on air currents. That's why a bird doesn't have to flap the whole time. It can float or soar.
fish need air because they won't be able to breath if they didn't have air, and fish need air badly because they spend most time in the water. fish need air as much as we do.
Perigrine falcons spend most of their time in the air as do most birds, so they don't "walk" they hop, and they probably don't do it very fast.
Except for a few seconds when leaping into the air, whales spend ALL of their time in the water. They cannot move on land.
Birds don't inhale air because they don't need to breath.
a couple hours, you will likely spend more time on the tarmac than in the air
The record for time in the air, is held by the Flying Alpine Swift. Three swifts stayed in the air for 200 consecutive days.