Delta Air Lines jets are seen at gates at Hartsfield-Jackson Atlanta International Airport in Atlanta, Georgia, U.S. December 22, 2021.
Delta Air Lines jets are seen at gates at Hartsfield-Jackson Atlanta International Airport in Atlanta, Georgia, U.S. December 22, 2021. Reuters / Elijah Nouvelage

U.S. passenger airlines carried 670.4 million passengers in 2021, up 83% over 2020 levels but still down significantly from pre-coronavirus pandemic levels, the Transportation Department said on Monday.

The department in preliminary data said airlines carried 303.6 million more passengers in 2021 but 245.9 million fewer, or 27%, than in 2019. In 2019, domestic flights accounted for 88% of all passengers, while domestic trips accounted for 91% of all passengers in 2021, and international flights accounted for 9%.

In December, U.S. airlines carried 66.3 million passengers, 118% more than the same month in 2020 and 16% fewer than in December 2019.

U.S. air passenger travel fell by 60% in 2020 to the lowest level since 1984, down 549 million passengers over 2019.

Airlines for America, an industry trade group, said air travel was down 25% in late January, with domestic flights down 23% and international air travel down 38% and business travel still remains down about 51% over pre-pandemic levels.

The group said its members were operating 14% fewer flights in January below pre-pandemic levels.

The Transportation Security Administration said in the week ending Feb. 13, it screened 24% fewer passengers than 2019 levels.

Airlines around the world are expressing optimism that travel will rebound this spring and summer as the Omicron variant's spread diminishes.

Last month, U.S. carriers American Airlines and United Airlines said a recovery in passenger traffic was likely to resume in March after a blip caused by the Omicron coronavirus variant.

Starting in early 2020, Congress awarded U.S. airlines a total $54 billion in government assistance for payroll costs that expired in September 2021.