You know, I think it's quite satisfying when you see people downloading your builds and some even go on to create amazing variations of it. This community has proven many, many times (and still does!) that they can massively improve upon a plane that wasn't built by them.
And you know the big, big benefit of this? Both the original creator and the "successor" are benefiting from this.
The creator gets points (7, to be more exact) for each upvote the successor plane gets, and the successor gets his fair share of upvotes for improving upon the original. One other benefit would be that the creator could learn something from the successor.
To give you a concrete example: RodWan's F-14 which itself massively improved upon suzutuki's F-14. So, what's the catch here? RodWan made it a successor to suzutuki's F-14 and (even if it wasn't needed) gave him credit for the original. Both learnt something new from each other's work. In the end, both were winners.

But where do I want to get with this? I want to say this: always credit the original creator. If you're making a variation of a plane, always make it a successor of that plane. There is nothing to lose from doing that.

This community is known for being one of the nicest around the Internet. Maybe it's because we aren't that many; maybe it's because we've learnt that each of us is different in their own way. But the main point is:

Be nice with everybody. Always give people credit for their work.