Moving from First Officer to Captain is a significant career milestone that depends on both regulatory requirements and airline-specific seniority. By law, a pilot must hold an Airline Transport Pilot (ATP) certificate, which requires a minimum of 1,500 total flight hours. However, most major commercial airlines set their own much higher internal thresholds, often requiring between 3,000 and 5,000 hours before a pilot is eligible for a "command" position. Beyond the raw numbers, the transition is heavily dictated by a "seniority list." Even a highly experienced pilot must wait for a Captain's slot to open up as more senior pilots retire or the airline expands its fleet. At fast-growing low-cost carriers, a First Officer might "upgrade" in as little as 4 to 6 years, while at major legacy carriers, the wait can stretch from 10 to 20 years. The process also involves a rigorous "Command Course," which includes advanced simulator training and psychological assessments to ensure the pilot can handle the ultimate responsibility of the aircraft and its passengers.