The med crew where I work call the helicopter  

Aircraft, including fixed wing, rotary wing, lighter than air, spacecraft, etc have always been referred to as ships. Have you heard of the Starship Enterprise? Both have pilots and Captains. Both have decks. Both use tugs. Airplanes and ships both have rudders, propellers, spars, ribs, trim. Speed is measured in knots. Both have cockpits. I'm sure there is more. Please add to the list.

Referring to any aircraft as a "ship" is a term of endearment. I like it and I use it.