[okie01]

There are numerous defenses a kit maker could use to invalidate such a patent, copyright or trademark suddenly being asserted against them after decades of unchallenged royalty free use.

Of course, there are. But the price of asserting them in a court of law -- that's the rub. Boeing, Lockheed, et al are lawyered-up and can pursue legal action in perpetuity. For their part, kit makers are looking at legal fees that would dwarf their profit margin.

[fso301]

Of course, there are. But the price of asserting them in a court of law -- that's the rub. Boeing, Lockheed, et al are lawyered-up and can pursue legal action in perpetuity. For their part, kit makers are looking at legal fees that would dwarf their profit margin.

The big companies have a risk that far exceeds any potential legal cost, that being, they have allowed their patents, trademarks and copyrights to be freely used for decades. In such circumstance, a company is at serious risk of losing such rights.