Is it permissible for a divorced woman to travel or return to her country without a mahram to marry her ex-husband if he is unable to travel to her?

The majority of scholars hold that it is impermissible for a woman to travel without a mahram, except in cases of extreme necessity, such as emigrating from the land of disbelief. However, some scholars have permitted travel when there is no fear of fitna (temptation or discord), even if it is not for a necessity, especially by airplane. Therefore, if a woman needs to travel and cannot find a mahram, and her journey is safe, there is no impediment to adopting the opinion of those who permit it.