...Air Transport Services Group, Inc.'s (ATSG) Ba2 corporate family rating reflects the company's strong position as one of the world's leading providers of air cargo fleet leasing and related services, including crew, maintenance and insurance (CMI) services, as well as its strong earnings prospects from its growing fleet, high margins and effective liquidity management. ATSG's earnings and cash flow have been more resilient than lessors of passenger aircraft due to the operating strength its cargo aircraft leasing business, particularly the leasing and CMI services associated with the time-definite package delivery network operations of key customers including Amazon.com, Inc. (A2 positive) and DHL (owned by Deutsche Post AG, A3 stable). ATSG's credit challenges include its high customer concentrations. In 2020, the US Department of Defense, Amazon, and DHL accounted for 31%, 30% and 12% of revenues, respectively. This challenge is partially offset by the benefits from the high credit quality...