All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If the ears are protruding beyond the usual condition in a way that they are considered as a deformity, like bat ears, then this is a (physical) defect, so it is permissible to treat them with cosmetic surgery provided the operation does not lead to another harm.
For more benefit, please refer to fataawa 83177, 87848 and 190645.
Allaah Knows best.