Is it permissible for a woman to travel for Hajj without a mahram if her brother will meet her at Jeddah airport?

There is no impediment for a woman, if she does not find a husband or a mahram, to perform Hajj with a safe company of women, or of women and men. This is the view of the Malikis and those who agreed with them. Imam Malik said in Al-Muwatta: "Regarding a woman who has never performed Hajj, if she does not have a mahram to go out with her, she should not abandon Allah's obligation of Hajj upon her. She should go out in a group of women."

Accordingly, the woman should go out with trustworthy women until her brother meets her and she performs the obligation in his company.