U.S. airline traffic rebounded last year, flying 670.4 million passengers in 2021, with attendance up 83 percent over 2020 levels, according to the Transportation Department on Feb. 14. However, preliminary data showed that airline passenger volume is still below pre-pandemic levels. The report said that U.S. airline companies carried 303.6 million more passengers in 2021, but 245.9 million fewer than in 2019, a drop of 27 percent. The total number of passengers carried by U.S. airlines at the height of the pandemic was down by 60 percent, a drop of 549 million passengers from 2019, the lowest levels seen since 1984. The airline industry had gradually been recovering for the past year, with disruptions such as the arrival of the Delta and Omicron variant in the Summer and Winter respectively. Air travel restrictions, global lockdowns, COVID passes, mask mandates, and fear of contagion put a severe dent in travel plans. The …