Australia’s Qantas said the outbreak would cost it up to A$150m ($99m; £76m), while Air France-KLM estimated a hit of up to €200m (£168m).
Air France is extending a ban on Chinese flights until at least the end of March, while Qantas will cut flights to Asia by 15% until the end of May.
It comes amid concerns of the impact on the global economy.
Qantas estimated that the coronavirus would result in a 100m -150m Australian dollar hit for the financial year, once it had accounted for cutting flights.
In a statement chief executive Alan Joyce said: “Coronavirus resulted in the suspension of our flights to mainland China and we’re now seeing some secondary impacts with weaker demand on Hong Kong, Singapore and to a lesser extent Japan.
“We’ve also seen some domestic demand weakness emerging, so we’re adjusting Qantas and Jetstar’s capacity in the second half,” he added.
To avoid job losses the company also plans to freeze recruitment and ask workers to use up leave.
Source: BBC News