What is the ruling concerning the current retirement pension of a father who worked as a sales trainer for an airline company, given the suspicion regarding the impermissibility of his previous work due to the possibility of some people traveling for unlawful purposes, and what is the ruling concerning the children's benefit from this money?

Working in this profession is permissible. The general rule for professions is permissibility unless there is a reason for prohibition. The possibility of tickets being used for an unlawful purpose is not given weight, due to the overriding benefit in learning this profession. Scholars have stipulated the nullification of such considerations, and that benefits and harms are weighed. If the side of benefit outweighs, then it is not prohibited under the pretext of 'blocking the means' (sadd al-dhara'i'). An example of this is the cultivation of grapes, which is not prohibited out of fear of wine. Therefore, there is no objection to benefiting from the retirement salary.