MSP is not exactly unique, it is just one of the last places that operate that way. Only a few Locals still use Air Drivers -- Air Drivers are an endangered species companywide. Article 40 just made the full-time ground Teamsters turn on the part time air drivers. So, for years there have been grievances for many things about the Air Drivers.
Now that FedEx is rolling everything into their ground operation, UPS will get rid of the remaining Air Drivers... The two companies are always tit for tat. And, undoubtedly there is a push to layoff (and fire) drivers, because of the new contract. UPS might have to make 7,500 jobs but nothing is stopping them from firing 7,500 drivers.