Idaho Code § 21-110
The acquisition of any lands or interest therein pursuant to this act, the planning, acquisition, establishment, construction, improvement, maintenance, equipment, and operation of airports and air navigation facilities, whether by the state separately or jointly with any municipality or municipalities and the exercise of any other powers herein granted to the department are hereby declared to be public and governmental functions, exercised for a public purpose, and matters of public necessity. All lands and other property and privileges acquired and used by or on behalf of the state in the manner and for the purposes enumerated in this act shall and are hereby declared to be acquired and used for public and governmental purposes and as a matter of public necessity.
Idaho Code § 21-110