Denver-based Frontier Airlines said the previously reported...

Denver-based Frontier Airlines said the previously reported sale of its five McDonnell Douglas MD-80 jetliners to United Airlines is scheduled to be completed Feb. 4 upon final payment of $19 million . . . Western Micro Technology, Cupertino, said that merger discussions with IEI Inc. have been discontinued . . . Miami-based Knight-Ridder Newspapers Inc. completed the acquisition of Tradecenter Inc., New York . . . W. R. Grace & Co., New York, completed its acquisition of Santa Barbara-based Carrows Restaurants Inc. . . . Phoenix-based America West Airlines said it has gained approval to begin flying to John Wayne Airport, effective April 1. It will discontinue flights to Palm Springs . . . Sears, Roebuck & Co. said its Allstate Enterprises subsidiary completed the acquisition of Greenwood Trust Co., Greenwood, Del. .