They manifest a nature's sublimity. That is why Gabriel is represented with wings. Not that angels have wings, but that you may know that they leave the heights and the most elevated dwelling to approach human nature. Accordingly, the wings attributed to these powers have no other meaning than to indicate the sublimity of their nature.
Words: St. John Chrysostom (widely attributed)
Image: St Gabriel. 12th-century mosaic from the Byzantine part of La Martorana, also known as Santa Maria dell'Ammiraglio in Palermo, Sicily. © Marie-Lan Nguyen / Wikimedia Commons
Thank you: Ellie Findlay at "Does Not Wisdom Call"