Legal Question in Intellectual Property in California

Many companies that go out of business sell off, or have already sold off, their patent and other intellectual-property portfolios. Also, consider the possibility that the aircraft manufacturer licensed the right to create the model kits to the model manufacturer, and would expect you to do the same. Many years ago, I had as a client a firm that was in the business of checking on still-existing I-P rights for Hollywood, and while I no longer remember their name, I'm sure there are companies around that can do a quick and not-too-expensive trademark, copyright and patent clearance for you with respect to each proposed model. I think it would be taking an excessive risk to tool up for production without making some effort to find any I-P holders for each proposed reproduction.