Airlines are gearing up for their next big hiring need: airplane mechanics. And to meet that need, some are bringing new job training programs to Chicago. Changing plane technology, a wave of pandemic exits and, in some cases, an anticipated uptick in the number of planes in the sky have left some airlines searching for ways to boost the pipeline of available plane mechanics. If airlines fall short of maintenance technicians, passengers are likely to experience more flight delays, industry analyst Bob Mann said. And even if airlines are able to get new mechanics into training programs, the nee…