The U.S. Postal Service has tapped United Parcel Service as its primary partner for moving cargo by air, replacing FedEx, which had provided the service for more than two decades. The new contract between UPS and USPS will begin in late September and run through at least March 2030, the Postal Service said Monday. Under the agreement, UPS will handle domestic air transportation for USPS's first-class mail, priority mail express, and priority mail. […] The company plans to eliminate costs it had in place to support the Postal Service contract after it ends. Shares of FedEx fell more than 3% in afternoon trading. UPS shares, which traded higher premarket, were down about 1%.