What must each prisoner wear during the flight?

The requirement for each prisoner to wear restraint devices during the flight is a critical safety and security precaution. Restraint devices ensure that prisoners cannot escape or pose a threat to the crew and other passengers during air transport. The use of such devices is governed by regulations and policies that prioritize the safety of all individuals on the flight, recognizing the potential risks associated with transporting incarcerated individuals.

While other options might suggest various forms of clothing or attire, they do not provide the necessary security measures that restraint devices ensure. Casual outfits, standard prison uniforms, and comfortable clothing may be appropriate in other contexts, but they fail to address the crucial aspect of maintaining order and safety during air travel involving prisoners.