On a flight, the co-pilot acts as the second-in-command under the captain. This means that a co-pilot can often have lower-level responsibilities and can take instructions immediately from the captain during a flight.

In the hierarchical structure of a 2026 commercial flight deck, the second pilot is officially known as the First Officer. While colloquially referred to as the "Co-Pilot," the First Officer is a fully qualified pilot who shares all flying duties with the Captain. They typically sit in the right-hand seat and wear three stripes on their epaulettes, whereas the Captain wears four. On ultra-long-haul flights, you might also find a Second Officer or "Cruise Relief Pilot," who acts as a third crew member to allow the primary pilots to take mandatory rest breaks. Despite the "Second" in their title, they are often junior pilots in training or specialized relief crew. The First Officer's role is critical; they act as a "monitoring pilot" when the Captain is flying and a "flying pilot" when it is their turn at the controls, ensuring a redundant "four-eyes" safety protocol is maintained throughout the entire duration of the flight.