Is sailor a collective noun or a common noun?

The noun 'sailor' is a common noun, a general word for a person whose job it is to work as a member of the crew of a commercial or naval ship or boat; a general word for a person who goes sailing as a sport or recreation.

A collective noun is a word used to group people or things taken together as one whole in a descriptive way.
The collective noun is a crew of sailors (the noun 'crew' is the collective noun, a word for the group).