The maintenance division of Delta Air Lines is loading up for more work. Delta Air Lines Inc. (NYSE: DAL) said Thursday its TechOps group signed an exclusive engine maintenance agreement with Austrian Airlines, Austria's largest carrier, that covers PW4060 engine maintenance for up to six years supporting the airline's Boeing 767 fleet. Financial details of the deal were not released. TechOps, which employs more than 11,000 people, has years of experience operating and maintaining PW4000 engines…