You have to understand, these companies have teams of lawyers working for them and they need something to do. That's partly how this happens. You also have to consider that corporations usually aren't known for good decision making, especially as far as public relations are concerned. Of course, for the big aerospace companies, they probably don't care since we aren't buying their products anyway. However, for Honda, this could backfire in a big way due to all of their consumer products that we can afford. I would also note that it also depends on if you are making freeware or payware and whether or not you're using their logo without permission. I give plenty of Kudos to Boeing for their cooperation with PMDG. IIRC, Cessna has also had a working relationship with Eaglesoft, but I'm not sure.