On YouTube there’s a video about the vocation story of Fr. Joshua Waltz. You can find the video on the YouTube page for the Bismarck Diocese. Anyway – in his story he speaks of an incident that happened on a trip to Europe when he was 18. He was supposed to meet up with family at one point in Barcelona, after leaving Rome (and meeting the Pope), but his family was stranded in the States due to a flight cancellation.
He says that he had only enough money to buy water and some bread and so he went somewhere to watch a soccer game on tv. While there, he was approached by a man who offered to buy him a meal. Later after eating and separating, Fr. Waltz found himself in some trouble when confronted by a prostitute, he rebuked her propositions, but then suddenly a group of about 5 men appeared out of nowhere. He turned around to find that and the same guy who had bought his meal was behind him (who was rather large, Fr. Waltz describes him as a 6’5" black man) so needless to say that dissolved the situation.
Two weeks later in Madrid, hundreds of miles away from Barcelona, while walking down the street he bumps into the SAME man again and this time, Fr. Waltz offers to buy him a meal, returning the favor. As they’re eating and talking, Fr. Waltz sees his mother outside and tells the man to wait a minute so he can run out and grab her and introduce her to him. When he reenters the restaurant with his mother, he finds that the man is gone but he left a note on the table that read: “God bless, Michael”.
So … Fr. Waltz says that if anyone is wondering, St. Michael the Archangel is a 6’5" tall black man
So yes, Angels can appear in human form.