Since model matching generally comes with many challenges, how about loading the other players aircraft as a low poly/low detail model. I understand this would be challenging when it comes to aircraft installed from other sources than the marketplace, but for all aircraft inside of the marketplace I guess it should be possible.
The idea is to include the lowest level of detail available (exterior only) of every airplane on the marketplace into the base game (or possibly in an optionally downloaded package) and update it with every marketplace update.