Notwithstanding the provisions of any other law to the contrary, the governing body of any third class city with a population of at least seven thousand but not more than seven thousand five hundred located in a county of the third classification without a township form of government and with a population of at least twenty-seven thousand two hundred but not more than twenty-seven thousand six hundred may annex the area of any municipal airport located along a state highway within six miles of such city and areas contiguous to the municipal airport.