United Parcel Service, the world’s largest package-delivery company, announced yesterday that it will put a DaimlerChrysler fuel-cell car into service later this year in Ann Arbor, Mich., making UPS the first U.S. company to integrate fuel-cell technology into its commercial fleet. One or more fuel-cell vans will start delivering UPS packages in 2004. Not to be outdone, FedEx today unveiled plans to incorporate 20 diesel-electric hybrid trucks into its delivery fleet, part of a pilot project developed in cooperation with Environmental Defense. If the project goes well, FedEx may convert all 30,000 of its delivery trucks to hybrids over the next 10 years. Compared to the trucks the company currently uses, the hybrid models increase fuel economy by 50 percent, reduce nitrogen oxide emissions by 75 percent, and cut particulate emissions by 90 percent, FedEx officials said.