Demand for air cargo surged 6.9 percent in 2021 compared to 2019 pre-Covid levels and was up 18.7 percent from 2020 following a strong performance in December, the International Air Transport Association (IATA) reported Tuesday. This marked the second-biggest improvement in year-on-year demand, behind 2010’s 20.6 percent gain, since IATA started to monitor cargo performance…