Copyright issues have been discussed in detail here before. I will look for the link later.
I have to protect my own company intellectual rights, so I know a little bit about it:
1. You AUTOMATICALLY have copyright on anything you produce (there are exceptions, but not really relevant to this).
2. You must PROVE you have the copyright. There is an easy way of doing this.
3. You can register a trademark of a single name- think about Pepsi, McDonalds etc. This is much more formal than copyright and is done through the patent office of your country.
4. It makes no difference whether your infringement is for commercial gain or not. Copyright infringement is copyright infringement. The only difference is whether a company WISHES to pursue you and the level of damages it can be awarded.
5. If you make a MATERIAL (substantial) change to a logo you will be ok. But changing it in a non-subsantial way (say an odd pixel here and there) will still render you liable to legal action.
Capt. D: You are quite right in what you say. Cunard would apply for a trademark (amazed if they haven't). But, as said above, it makes NO difference if the infringement is non-commercial. Only that a) they are less likely to find out and b)they may not be bothered.
In summary: Unless you have WRITTEN permission you infringing copyright. Trust me, I had to take legal action in 2005 against copyright infringement for my company.
Stu