In volume 1, chapter 10 (https://mangadex.org/chapter/daeb4fd1-2c6b-4fbf-8ede-5727d0881efa/13) Osaka suggests that the Rudolph might not be a reindeer because of his red nose. So, reindeer flying is reasonable, but having a red nose is too much? Feels like Tomo should've said something then.