What should be done immediately after each takeoff regarding seat belts?

After each takeoff, it is crucial to inform passengers to keep their seat belts fastened due to the potential for turbulence or unexpected maneuvers in the aircraft's climb phase. This is a standard safety protocol that reinforces the requirement for passengers to remain secured in their seats until the captain determines it is safe to remove their seat belts.

This communication serves as a reminder of the importance of safety and helps to prevent injuries during the critical initial phase of flight when the aircraft is ascending. It also aligns with Federal Aviation Administration (FAA) regulations that emphasize passenger safety and the appropriate use of seat belts throughout the flight.

The other options, while related to safety, do not effectively address the immediate need for passengers to remain buckled in after takeoff, making it essential to prioritize the announcement that emphasizes keeping seat belts fastened.