The acquisition of any land, or interest in land, pursuant to this chapter, the planning, acquisition, establishment, development, construction, improvement, maintenance, equipment, operation, regulation and protection of airports, air navigation facilities and avigation easements, including the acquisition or elimination of airport hazards and the exercise of any other powers granted in this chapter to authorities and other public agencies, to be severally or jointly exercised, are declared to be public and governmental functions, exercised for a public purpose, and matters of public necessity. All land and other property and privileges acquired and used by or on behalf of any authority or other public agency in the manner and for the purposes enumerated in this chapter shall and are declared to be acquired and used for public and governmental purposes and as a matter of public necessity.