There is a little truth to just about everything people have said here.
But certainly those who don't plan on making their own drawings need to know what is available, how accurate it is, and must have a good supply of reference.
To suggest taking whatever drawing you find and using it without research is an over simplification.
There are SO many poor quality drawings out there and so many that are simplified. To do this right, and I believe this is one place where compromises shouldn't be made for arts sake, one must research the subject, get to know the shapes, contours and details, and gather all material available before even starting.
How you arrive at the "accurate" drawing is another thing. Whether you draw your own or trust other artists drawings, you must at least have some way of checking their accuracy.
The end of it is this; if you set out to create a representation of a historical object, be it a plane or a tank or whatever, there is no substitute for research.
No matter how good of an artist you are, no skill can make up for inaccuracy. How much accuracy is again the individual's decision.