Do passengers have to pay for the return flight because of the weather?

No need. If you can't reach your destination because of the weather, the airline will adjust the time to send passengers to your destination, but there will be a time delay and no extra charge.

The plane turns back, that is, the plane returns to the take-off point after taking off. As long as there are security risks that threaten the lives of passengers and crew on the plane, they may be the reason for the plane to return. Imagine that if these safety hazards occur when the plane is cruising at an altitude of 10,000 meters, there is no manpower, financial resources and material resources at high altitude, and no rescue can be carried out quickly anyway, so the plane can only descend to the ground quickly. In this case, if the plane is not far from the departure point, it will generally choose to return to the original airport. If it is far away from the original airport and the situation is urgent, we should consider alternate landing. These security risks generally include aircraft failure, crew failure to control passengers, hijacking, terrorist threats, sudden weather changes and unsuitability for flight. In short, all security risks may be the reason for the plane to turn back. In order to ensure the safety of passengers and crew, there is no luck in the civil aviation industry.