To earn certification and rating as different kinds of pilots, you need to log hours when you have been acting as the pilot in command (PIC).
To become a private pilot, you need to log 40 hours but to fly for airlines you need a massive 1500 hours of PIC flight time.
Just being up in the air doesn’t qualify as PIC hours. There are strict guidelines about what kind of flight experience counts as PIC experience.
Ultimately, to log hours as a PIC you need to be the pilot who has ultimate responsibility for the aircraft. This doesn’t necessarily mean you have to be the pilot manipulating the aircraft.
Let’s look at some scenarios for clarity. In all the following situations, you would be able to log PIC hours.
1. You are flying a single pilot aircraft alone.
2. You are in a two or three pilot aircrew, and you have been designated as the pilot in command.
3. You are acting as a safety pilot and have been designated as the PIC.
Note that in the last scenario, you may only log PIC hours for the time when the other pilot is flying wearing a vision limiting device.
The key to logging PIC hours in a multi pilot aircrew is establishing who is going to act as the PIC before takeoff. This needs to be agreed and logged by the other pilots.