Crossfire Design Inspiration?

Some kit design elements may have been inspired from old Estes Design of the Month winners. For years Estes ran the D.O.M. competition offering a $50.00 (later a $75.00) merchandise prize.
If you need some inspiration, check out the winers at JimZs, CLICK HERE 
The Estes contest rules said the models should be "New, original and different but they also need to be workable." To see the contest rules - CLICK HERE

Look at the fins on the Estes Crossfire, Kit #7220

Compare the fins on the August 1969 DOM winner, the Blue Lightning designed by Ivan Joe Sandman. The fin tabs were the big design element in his model.

Take a variant of the Blue Lightning fins, mount them on a shorter length BT-50 tube. Add the plastic nose and tail cone from the old Black Brant kit and you have the Crossfire.

Do the Estes designers borrow from older designs?
Sure, we all do. 
Your next new build might be found in the old MRN issues.