Is it permissible for a Muslim woman to travel without a mahram to attend a training course essential for her professional development, with her husband's consent, whether she is accompanied by a non-Muslim female colleague or a committed Muslim sister?

A woman is not permitted to travel for study without a mahram, unless there is a necessity. Her traveling with another woman does not make it permissible. She must seek a way for her husband or one of her mahrams to be with her; otherwise, she should postpone her studies. The mahram is not required to stay with her for residence if the place is safe; the mahram can drop her off and then return to accompany her [later].