The invention relates to a device for improving security in an aircraft during the operation of air traffic. The invention is characterized in that a security zone (2'), which can be sealed off by controllable access doors (25, 26) and monitored by sensors (24, 31), is provided between the passenger cabin (3) and cockpit (1) areas. The invention also relates to methods for improving security during the operation of air traffic, using said device. The advantage of the invention is that the penetration of the cockpit by unauthorized persons, who could neutralize the functions of the pilot or operational components, can be prevented. Even in the case of a present threat or a terrorist attack, involving the taking of hostages or a threat with the use of violence, the pilots in the cockpit are protected effectively.