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That of course begs the question : Why would a buyer who intends to operate the aircraft not want to register it for his peace of mind as well as the previous owners .

You said the current owner (your buyer) is already in the process of transferring ownership to someone else. He might be a shady/unlicensed aircraft broker who doesn't want to pay taxes/insurance while the plane is waiting to be sold. Some small-time used-car dealers operate like that.

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