Mich. Comp. Laws § 259.79: Carrying or display of registration certificate or assigned number; exception.

Sec. 79.

The state registration certificate issued by the commission shall be carried in the aircraft at all times. Each aircraft shall display the number assigned to it by the United States or a foreign country.

A person shall not carry or display upon an aircraft a registration certificate not issued for the aircraft or not otherwise lawfully used on the aircraft.

Historic or restored aircraft or an authentic replica of a historic aircraft are not required to display any external state-required registration markings.