It is hereby found, determined, and declared that the creation of an authority and the carrying out of its corporate purposes is for the benefit of the people of the State of Nebraska, for the improvement of their welfare and prosperity, and for the promotion of their transportation, and is a public purpose and a matter of statewide concern, and that projects operated by authorities are essential parts of the public transportation system. The State of Nebraska covenants with the holders of bonds, issued under the provisions of sections 3-610 to 3-621, that authorities shall be required to pay no taxes or assessments upon any of the property acquired by them or under their respective jurisdictions, control, possession, or supervision, or upon the activities of authorities in the operation and maintenance of projects, or upon any charges, fees, revenue, or other income received by authorities except motor vehicle fuel and aviation fuel taxes, and that the bonds and notes of authorities and the income therefrom shall at all times be exempt from taxation, except for transfer and estate taxes. This section shall constitute a covenant and agreement with the holders of all bonds and notes issued by authorities. This section shall not be construed to affect the obligation of a lessee to pay taxes if taxes are due under sections 77-202, 77-202.11, and 77-202.12.