Section 49L. No transfer of registration of aircraft of which the owner’s registration has been suspended shall be deemed valid or accepted by the commission, unless the transferor or transferee demonstrates to the satisfaction of the commission that the transfer of registration is the result of a bona fide transaction of purchase and sale, and not for the purpose, or with the effect, of defeating the purposes of sections forty-nine B to forty-nine R, inclusive. Nothing in this section shall affect the rights of any lessor or conditional vendor, chattel mortgagee, or other person holding a security interest in any aircraft registered in the name of another as owner who becomes subject to the provisions of said sections.