Eh, some volunteer places will take you as just a driver, but will make you sign a contract agreeing to take an EMT-B course within 6mo to a year. As a driver with an EMT-B cert or at least a first responder cert, you will much more valuable, esp on-scene.
As a job, you can basically forget it unless you have an EMT-B or FF cert minimum.
To drive an ambulance, you'll need to take an EVOC class (emergency vehicles operations class).
To be a flight operator, to be honest, the military will be of the most assistance with that if it is something you are willing to look into. They pay you to go to the class.