Praise be to Allaah.
It is not permissible
for a woman to travel without a mahram because of the general meaning of the
hadeeth of the Prophet (peace and blessings of
Allaah be upon him): “It is not permissible for any woman who believes
in Allaah and the Last Day to travel except with a mahram.”
because the purpose for the mahram being there is so that he can protect her
and take care of her, especially if any emergency arises, and travel is subject
to emergencies regardless of the length of time involved. Whatever people regard
as “travelling” is like this, and is subject to the rulings on travelling.
more on the rulings on mahrams, see Question # 5538
Sheikh Muhammed Salih Al-Munajjid