Does the pilot choose what plane to fly and can they chose to fly or not?
Commercial airline pilots can choose the companies for which they want to work. That’s where most of the choice stops. An airline can tell its pilots which airplanes to fly and where to fly them, and when they must fly. The pilots are simply the airlines employees, so they have to do what they are told. There are a few protections. Pilots can only fly aircraft for which they have the appropriate license (type rating), so if they are rated only to fly a 737 or 767, they cannot fly a 747 (but they airline can compel them to obtain a new rating so that they can fly a different airplane). Their working hours are limited in certain respects by law, and the airline cannot force them to work beyond these limits; but the airlines have sneaky ways of getting pilots to work as much as possible, and sometimes pilots have to work when they are tired. A pilot who gets sick can refuse to fly, but an airline may get tired of dealing with a pilot who seems to get sick too often.
