In my FTL career, I've managed to unlock one or two of the other ships in the hangar, but there are still some that are unavailable.
One thing that I've found is that there tends to be a relatively complex series of events that leads to unlocking a new ship type. It seems like for at least some of them, a measure of advance planning and correct event responses is required.
What are all the ships available, and how do I unlock each one?