More than three quarters of all land animals fly, from butterflies and birds to beetles and bats.Some birds can stay airborne for hours with only an occasional flap of their wings, flies can hover and perform split-second turns, while bats can execute their precise maneuvers in total darkness.How do they do it? Find out the secrets of animal flight - the principles that keep fliers as different as ladybugs and eagles aloft.And discover some puzzles that scientists haven't yet been able to solve - nature's mysteries of flight.