Is it better for a flight attendant to conceal alcohol from passengers to reduce demand, or to display it normally as a right of the passenger? And does the sin differ between someone who serves alcohol once a month and someone who serves it ten times, given that both are compelled and displeased with this action?

It is not permissible for a flight attendant to serve alcohol to passengers, as this involves condoning evil and assisting in it. The Prophet, peace and blessings be upon him, cursed ten categories of people in relation to alcohol, including its pourer and its carrier. Therefore, it is obligatory for the flight attendant to spill it, destroy it, or at the very least, prevent its consumption and forbid it. Otherwise, he must leave this job and seek permissible work, because "there is no obedience to a creature in disobedience to the Creator."