A Dealer's Aircraft Registration Certificate, AC Form 8050-6 is valid only in connection with use of aircraft—
By the owner of the aircraft to whom it was issued, his agent or employee, or a prospective buyer, and in the case of a dealer other than a manufacturer, only after he has complied with § 47.67;
Within the United States, except when used to deliver to a foreign purchaser an aircraft displaying a temporary registration number and carrying an airworthiness certificate on which that number is written;
While a certificate is carried within the aircraft; and
On a flight that is—
For required flight testing of aircraft; or
Necessary for, or incident to, sale of the aircraft.