Air Transport Services Group, Inc. (ATSG) is currently mired in multiple headwinds, which, we believe, have made it an unimpressive investment option.Let’s delve deeper.Southward Earnings Estimate Revisions: The Zacks Consensus Estimate for the current-quarter eanings has been revised downward to 29 cents per share from 32 cents over the past 60 days.  For the current year, the consensus mark for earnings has moved 6.6% south in the same time frame. The unfavorable estimate revisions indicate brokers’ lack ...