Whenever any such city has acquired fee simple title to real estate for use as an airport or flying field, and whenever in the opinion of the governing body of such city, it would be advantageous to purchase additional real estate consisting of nine (9) acres, more or less, of additional real estate in order to extend the runway of such airport, and to sell sixty-five (65) acres, more or less, of real estate which is no longer needed or useful in the operation of such airport; such cities shall have the right to sell said real estate and to purchase such additional real estate. Before conveying or acquiring said real estate, such governing body shall by resolution find and determine that same is in the best interests of the city. Thereupon, the governing body of any such city, by its mayor and clerk, is hereby authorized to make, execute, deliver, and accept a good and sufficient deed or deeds of conveyance in order to carry out the provisions of this act.