The company now expects full year underlying earnings between $210m and $235m.
It's previous forecast was between $260m and $270m.
Chief executive Adrian Littlewood said passenger numbers for the first 10 days of this month were down 18 percent on last year, and he expects further decreases in the next few months.
Trading in the company's shares was halted yesterday afternoon as it revised its financial forecasts.
The share price has fallen 16 percent over the past three weeks.
Yesterday the US suspended all travel from Europe to the United States for the next 30 days because of the Covid-19 coronavirus. The travel order which starts at midnight on Friday (US time) applies to 26 European countries but excludes Britain.