Flying is an evasion ability that prevents a creature from being blocked except by creatures with flying or reach. It is one of Magic's most common ways to make creatures harder to stop in combat.
Empyrean Eagle strengthens flying creatures, Jubilant Skybonder makes them more difficult to target, and Watcher of the Spheres can reduce their casting costs. Angels, Birds, Spirits, Faeries, and Dragons are among the creature types most commonly associated with flying.