Hazrat Moulana Ashraf Ali Thanwi (rahmatullahi ‘alaihi) once mentioned that he received a letter from a person enquiring whether it would be permissible for him to travel with one of his elderly female relatives who wished to accompany him for hajj. Moulana Ashraf Ali Thanwi (rahmatullahi ‘alaihi) replied that as long as there is no mahram accompanying her on the journey, it will be impermissible for her to travel.
An ‘Aalim present asked that is it not that the reason for the prohibition of a woman travelling alone for hajj is due to being alone (hence if she is in company, it should be permissible). Hazrat Moulana Ashraf Ali Thanwi (rahmatullahi ‘alaihi) replied in the negative. Thereafter he explained that the reason for the prohibition (as explained by the Fuqahaa) is that generally many difficulties and evils occur during the journey. In the case where a woman travels alone, there is no one to assist her or come to her aid. On the contrary, in the case where she is accompanied by her mahram, then she feels (mentally and physically) secure that in the event of some difficulty, she would be able to easily call out for him and seek his assistance. However Hazrat Moulana Ashraf Ali Thanwi (rahmatullahi ‘alaihi) then said that these explanations that we present are mere logical explanations which appeal to our comprehension and understanding. The reality of the matter is that this is the law of sharee’ah which we are unable to fully comprehend and encompass its divine wisdom. Hence, we are bound to believe in it being correct and accept it whether we understand its wisdom and logical reasoning or not. (Malfoozaat Hakeemul Ummat 1/87)
Source: Ihyaauddeen.co.za