This episode looks at powered flight, revealing why peregrine falcons can top 200 miles an hour, how a hummingbird is a slave to its own rather manic lifestyle and that the albatross’s secret to flying for free is its nose. Heavyweight beetles break the rules to find love, a devious sparrow-hawk uses agility to execute a lightning-fast raid on his prey and half a million mother bats dominate the sky above, and below, the ground with a dazzling display of aerial prowess.