A private airport on Albuquerque's north edge is going out of business after 40 years. Coronado Airport's owner, the pueblo, was shutting it down Nov. 30 in preparation to develop its 268 acres. Preliminary plans call for an office and retail center on the land, though no timetable for development has been set. Tribal leaders announced in September they would close the airport because of drainage problems and safety concerns which would cost too much to alleviate. Coronado opened in the early 1960s. At the time, it was an isolated airstrip parallel to what is now Interstate 25. Today, the field is hemmed in by housing developments and to the north, by Sandia's new casino. William J. Fisher, a business development specialist for Sandia, said the 60-day notice to vacate was tied to a termination clause in the airport's lease agreement. Operators had complained they couldn't find a home for 100 airplanes in just two months. About 25 planes remained at the field Nov. 29. Fisher said improvements would being soon on a storm water channel that crosses the runway which would have required shortening the runway, already "pretty minimal" and used by only the smallest planes.