Final answer:
Aircraft seatbelts must be worn by all pilots at all times during flight while they are at their control stations in the cockpit, as part of standard aviation safety regulations.
Step-by-step explanation:
Aircraft seatbelts are required to be worn by all pilots at all times while seated at their control stations in the cockpit during flight. This is a standard safety regulation enforced by aviation authorities to ensure the security of the flight crew and the integrity of the control station in the event of unexpected turbulence or other in-flight issues. In the given case study of Antônio's first flight, the pilot informs passengers when they may remove their seatbelts, but this does not apply to pilots who must keep their seatbelts fastened throughout the flight.