Flutterby™! : Patents and airplanes

While we're on the aviation thread, an interesting twist where owners of Lake Amphibian aircraft will be forced to pay patent fees for a required Airworthiness Directive, there are some interesting confusions because some of them had a third party fix the aircraft, but since Lake Aircraft has now sold the patent rights to Enpat, Lake is now claiming it can't do anything. Lock-in isn't just a software thing, hardware companies can lock you in to buying only their fixes for their earlier mistakes.