I'm with Prune Fan on this one.
Choppers? I've never heard anyone seriously involved in the helicopter world who calls them that - apart from whichever Aussie bleeder named the VRPs for Bankstown.
Helos? What a horrible abortion of a word. I've heard people trying to spread that one into the UK, but thankfully it falls on stony ground.
It's a helicopter. Ship is acceptable. Old bus will do.