Is it permissible for a woman to travel with her female colleague to attend a three-day scientific conference, with men of high moral character present in the delegation, and with the husband's approval? And is this considered a safe companionship?

A woman is not permitted to travel except with a mahram, due to what was narrated by Al-Bukhari and Muslim from Ibn Abbas, may Allah be pleased with them both, who said: The Prophet, peace and blessings be upon him, said: "A woman shall not travel except with a mahram." This applies even if the company is trustworthy or the husband agrees, as he is not allowed to grant permission for it. If the conference is important, each woman can convince a mahram to travel with her.