The Seattle-based online retail giant has agreed to sublease a 278,670-square-foot "sortation center" — a key part of Amazon's package delivery network — that's now under construction just south of a company delivery station in the airport's Peak Innovation Park, Greg Phillips, the city's aviation director, said Friday. Amazon agreed to sublease the sortation center from a limited liability company that public records indicate was formed by Suncap Property Group of Charlotte, N.C. Suncap's limited liability company, in turn, is constructing the building and this week completed a 75-year agreement, with a 15-year extension option, to lease the 37.4-acre sortation center site from the airport.