Section 68.115 - Powers of commission1. Any power or powers, privileges or authority exercised or capable of exercise by a public agency of this state may be exercised and enjoyed jointly with the Mid-America port commission according to the powers delegated to the commission pursuant to sections 68.100 to 68.120.2. A public agency of this state may enter into a letter of understanding with the commission to advance the* purposes of the commission.3. The Mid-America port commission shall exercise no control over the operation of port authorities established pursuant to sections 68.010 to 68.070, except by voluntary agreement between said port authority and the commission.