United Airlines CEO Scott Kirby did not mince words during the company’s Wednesday fourth-quarter earnings call, terming industry capacity aspirations for 2023 “simply unachievable.”  He said that all companies, including airlines and the U.S. Federal Aviation Administration, need to staff at higher levels, an effort he said was hindered by such constraints as the ongoing pilot shortage, lower experience levels, elevated sick rates because of Covid and some state legislation that makes calling in sick easier. “We believe that any airline that tries to run at the same staffing levels it had pre-pandemic is bound to fail and likely to tip over to meltdown anytime there are weather or air…