United Airlines Holdings Inc. is slashing its flying schedule and implementing a series of cost-cutting measures in some of the most drastic actions by a U.S. airline to date as the spreading coronavirus has depressed air travel demand.

The steps followed a meeting between U.S. President Donald Trump and the heads of major U.S. airlines including United at the White House on Wednesday, where they discussed the impact of the coronavirus crisis on the industry.

In a letter to employees, United said it was reducing U.S. and Canadian flights by 10% and international flying by 20% in the month of April and eyeing similar cuts in May in response to demand.

The airline is also freezing hiring, delaying merit-based salary increases and offering employees the option of taking a voluntary unpaid leave of absence in an effort to get ahead of the financial impact of the crisis.

Company leaders warned employees the cuts may not be enough depending on future demand.

Shares of U.S. airlines have plummeted over the past week as it became clear that the coronavirus, which emerged in the central Chinese city of Wuhan late last year, was spreading around the world, with more new cases appearing outside China than inside.

Concerns over the effect of reduced travel demand on airlines stoked fears of a financial bailout for the sector, an idea that the head of the U.S. Chamber of Commerce on Wednesday moved quickly to dismiss.

Trump also said on Wednesday that the airline executives had not asked for a bailout.

Until now, United and other U.S. carriers had only reduced flying to the areas most hit by coronavirus cases, though international rivals Cathay Pacific Airways Ltd and British Airways have recently announced broader reductions.

"The experience of these and other foreign carriers is a further sign that the impact of COVID-19 on our industry - both internationally and here in the U.S. - continues to evolve rapidly," United said in the letter, signed by CEO Oscar Munoz and President Scott Kirby.

The rapid, global spread of the virus has forced airlines to abandon their usual strategies for crisis management.

Hours earlier, the head of the U.S. Chamber of Commerce said that the government will not need to bail out U.S. airlines in the wake of sagging travel demand due to concerns over the coronavirus.

"We don't need any bailouts here," U.S. Chamber Chief Executive Tom Donohue said at a news conference with travel leaders aimed at reassuring Americans to keep traveling. "Bottom line is we're going to run just like business as usual - with a little higher heartbeat and get it done."

Trump said at a meeting with airline executives later on Wednesday that they had not sought any financial assistance. "We haven't discussed that," Trump said.

Roger Dow, who heads the U.S. Travel Association, said at the same event as Donohue that he considers a bailout unnecessary, but suggested the government could take steps to boost demand for travel.

Travel industry officials said the government could reinstate some tax incentives to encourage business travel and spend additional funds to promote U.S. travel destinations.

Analysts at Rabobank said in a research note on Wednesday that "financially, given the huge blow that airlines and other service-sector firms are likely to suffer, we are also certain to see state aid and/or bailouts to key firms, even if this is technically illegal in some countries currently. We might also face some temporary quasi-nationalizations once again, as during 2008-09."

Trump and Vice President Mike Pence met with the chief executives of American Airlines, United, Southwest Airlines Co and other major airlines to discuss the coronavirus outbreak and the business outlook for the industry.

U.S. airline stocks have fallen - some as much as 40% in recent weeks, though they recovered slightly on Wednesday.

Many businesses have restricted employee travel and numerous business meetings and conferences have been canceled in recent weeks.

Since the virus surfaced in China late last year, it has continued to spread in South Korea, Japan, Europe, Iran and the United States, and several countries recently reported their first confirmed cases, taking the total to some 80 nations hit with the flu-like illness that can lead to pneumonia.