For the helicopters you can put them on cargo ships and then it is cheap as heck.
For the fixed wing aircraft, I don't know is two cross hemisphere flights a year really more carbon footprint than two identical fleets of highly expensive materially intensive aircraft?
I don't know.... maybe but I kind of doubt it since if I wanted to buy an airplane it would be much cheaper to buy it from the otherside of the world premade than attempt to build it myself... so?
I think it is an interesting question to ponder is what I am saying.