Actually, the design of the F-15 (and all military vehicles) is the property of the US government, built under contract by private companies. The payment for that design (which is usually funded by the US military) is the awarding of the contract to build the aircraft. Taxpayer dollars design the airplanes and build the airplanes. The companies want to charge licensing fees because they feel it's their intellectual property. In fact, if they were to license say the F-15, they'd be collecting a royalty for a product that's not technically theirs. It's like writing a book... I wrote a book (really, I did), the publisher paid me to write the book, and he paid to have it printed. Even though I wrote the bookand my name is on the cover, and I designed that cover, I'm not entitled to print my own copies and sell them, nor am I entitled to demand a royalty from you if you decide to Ebay a copy of my book.
NASCAR, auto companies, and trademarked names (DuPont, Wal-Mart, Viagra, Home Depot) are intellectual and actual properties of the originators, and as such are subject to licensing and royalty agreements.
In the case of the railroads and auto industry, it was a financial matter, they were looking for revenue. In the case of military subjects, it's based on the controlled usage of intellectual property. They (Boeing, General Dynamics) feel that if they don't keep reins on the little guys (namely the model companies) then it sets a precedent for it to happen on a larger (and potentially damaging) scale.
There's nothing anyone can do to stop Boeing from imposing licensing and royalities on 747 models. There's also nothing to prevent Sikorsky from doing the same with it's non-military choppers. But anything that's ever received a military designation by the US government is the property of the people...and we've already paid for it with our tax dollars.
This does have ramifications at several levels, since it sets a precedent that could impact things all over the world (in our little hobby). Let's look at the four big aircraft companies...Boeing, Northrop-Grumman, Lockheed-Martin, and General Dynamics. Between them, they own the rights to North American, Chance-Vought, Brewster, Consolidated, and McDonnell-Douglas.
This isn't just about F-15s, it's about Corsairs, Mustangs, and Flying Fortresses as well. Electric Boat built PT boats, now they build submarines, General Motors built aircraft and tanks, so it's about PT-109 and TBMs and FM-1 Wildcats.
Should we have to pay a royalty to build a likeness of a Flying Fortress, just because Boeing built them 60 years ago?'
It's a very convoluted issue, with lots of little pros and cons on both sides. The aerospace companies don't have an issue with the hobby shop owner who sells a $25 kit that bears the name of one of their products...BUT...they have to start defending their product trademarks somewhere, and we (the model community and industry) were the easiest ones to go after and try to make an example of.
Jeff
Now, if I could just convince the Air Force to give me one of MY F-15s, life would complete!!!