Is it permissible for a woman to travel by plane without a mahram if her solo travel duration is two hours and fifty minutes, and the solitude ceases with the husband's presence at departure and the father's upon arrival, and this is for a family visit, with the lack of funds being the reason for the husband's inability to travel?

The prohibition against a woman traveling without her husband or a mahram (definition) has been reported. A non-pubescent male is not considered a mahram by Islamic law. A woman sins if she travels without a mahram unless there is a necessity. The duration or mode of travel, or the fact that the husband bids her farewell and another mahram receives her, does not affect the ruling. What is required is the presence of a mahram during the journey. The wisdom behind this prohibition is that dangers persist even if a woman travels by airplane. What is obligatory is to comply with the divine command and be patient until it becomes possible for her to travel with a mahram.