... and they can't sleep when there are flights and the catapult sledges are rushing to the brakes with a lot of noise. That's why several aircraft carriers always belong to a formation. One for one half of the day, the other for the other half of the day.Pilots are humans. They need to eat, sleep, go to the toilet, and yes they have other duties besides flying an aircraft ...
In the past, the flights were shorter, the aircraft were smaller and the squadrons were larger; up to 200 missions were flown per day. Not anymore these days, but the planes stay in the air for many hours and are refueled there.
The number of missions flown is not a relevant measure.