Hello TB!
You know that the favourite scale for paper planes is 1/33 right? I'm not sure if in this scale C-46 or DC-6 would be reasonable sized - anyhow I didn't find any paper models of them availalble. C-46 was too exotic in Europe and DC-6 was a capitalist machine - polish airlines used Il-18 instead. But if you wanted a C-47, there's a paper model of it in 1:33:
As this googled photo shows, it's a nice big machine - not a weekend build, neither.
As for that cruise ship - here you could find something but closer to 1:400:
OK, you can rescale this to 1:160 - then it will be 2,1 m long - you don't have this much space on your layout, right?
How about this baby - it's in 1:100 and it would be closer to 300mm long if you rescale it to 1:160:
I have also found this thing in 1:200:
It's been build by the East Germans - I'm not sure if you can convert it to something American? But it starts getting big, anyhow.
Thanks for lookin' and have a nice day
Paweł