What is the purpose of the thumb up signal before taxi?

The thumb up signal before taxiing serves primarily to confirm cabin readiness. This gesture is a key communication tool between the flight crew and cabin crew. It ensures that the cabin crew has completed all necessary pre-taxi checks and that the aircraft is safe for taxiing. When the pilots receive this signal, they can proceed with confidence that the cabin is secure, passengers are seated with seatbelts fastened, and any loose items are stowed appropriately. This is crucial for maintaining safety and ensuring a smooth departure process.

While there may be other signals used for different purposes, the thumb up specifically aligns with confirming that the flight's conditions are met for taxiing, highlighting its importance in the sequence of pre-flight operations.