A Little About Pigeon Post
In medieval times pigeon post was established for sending messages between towns and nobles. Nobles would raise messenger pigeons (descended from Rock Pigeons) in dovecotes, crate some pigeons up, and exchange crates of birds with other towns/nobles to carry messages back. Most birds can physically do it, but few have the rock pigeons homing instinct, and even fewer are faster or able to fly longer distances than pigeons. Besides, the excess squab provided meat as well.
Taking this concept to a medievalish setting with magic where birds can pull flying (levitating) chariots or boats and suddenly messenger pigeons pulling levitating body or loot bags is but one option available to PCs ..
Designer of Lead