Sun & savings at Southwest Florida.(AIRPORTS)

WHEN THE NEWEST commercial airport terminal in the US opens this month, Ft. Myers' airline tenants will get not only a complex twice as large as the old one but also a commitment by the airport director to lower their operating costs. Southwest Florida International Airport's carriers now pay a relatively low per-enplaned-passenger charge of $6.75 and a landing fee of $1.12 per 1,000 lb. of landed weight. Executive Director Robert M. Ball tells ATW, "I expect the landing fee to go to 50 cents within three years," and he believes the new facilities will provide other economies to i