The three months to the end of December closed with a net loss of 1.9 billion dollars, the company announced in Chicago on Wednesday after the close of US stock market trading for the day, Deutsche press agency (dpa) reported.
A year ago, the company recorded a profit of 641 million dollars. Revenue slumped 69 percent to 3.4 billion.
First quarter estimates for 2021 weren't optimistic either, with the company expecting to be down 65-70 percent on 2019 earnings for the same period.
With the pandemic bringing most air travel to a halt, full-year results also showed major losses. United suffered a 7.1-billion-dollar loss in 2020, after earning 3 billion dollars the previous year. Revenue fell 65 percent to 15.4 billion dollars.
The annual report was lower than market expectations, and shares dipped into the negative after markets closed.
