WASHINGTON—The U.S. Transportation Security Administration (TSA) has proposed $644,398 in fines for 922 COVID-19 mask violators since February 2021 on commercial flights, in airports and train stations, or on public transit services, the government reported on Monday, a dramatic jump in recent months. According to the government report, all but 44 of the TSA fines were for failing to wear masks as required on airplanes or, less often, in airports. The rest covered unmasked passengers in surface transportation like transit, rail, and bus. The agency said it has also issued warnings to more than 2,700 travelers after more than 7,000 reported incidents since the transit mask requirements took effect. In late October, TSA said it had proposed $85,990 in fines for 190 mask violators and issued warnings to more than 2,200. Last week, TSA said it was extending mask requirements at airports and on airplanes through April 18. Since the …