Is a woman sinful if she travels alone for work, study, Hajj, or Umrah without a Mahram?

It is not permissible for a woman to travel without a mahram according to the majority of scholars, except in cases of necessity, such as migrating from a land of disbelief to a land of Islam.

Some scholars have permitted travel without a mahram when there is no fear of fitna (temptation or discord), especially by airplane.

If your travel is for the obligatory Hajj or Umrah and you do not find a mahram, then there is no blame upon you.

As for study and work, do not travel for them except in cases of necessity or dire need.

It is advised to marry a righteous man.