AnswerA flagship has different uses in a fleet or flotilla of boats and ships. It is the command vessel, which means it is the vessel in which commanding officers for the entire fleet will be present. For a naval fleet this is usually person or persons with the rank of admiral or above.
The term has also been used by vehicle manufacturers, where the 'flagship' is generally the top of the line vehicle for that manufacturer. Sometimes is also the model that sells most and keeps that company afloat.
It's worth noting that, although the admiral is based on the flagship, he is not the captain of that flagship.