US airlines announced additional steps Friday to ground planes and curtail executive pay as they prepare for an unprecedentedly bad travel market in the near-term.

Demand for service at Delta Air Lines is "declining at an accelerated pace daily, driving an unprecedented revenue impact," Chief Executive Ed Bastian said in a letter to employees that announced the carrier will cut overall capacity by 40 percent.

Bastian also announced that he was forgoing 100 percent of his salary over the next six months and that Delta would park up to 300 aircraft and reduce capital spending by at least $2 billion.

The measures are more extreme than those outlined only three days ago. Since then, President Donald Trump announced a 30-day travel ban to Europe, worsening an already difficult environment for the industry.

Airplane
A Delta plane is pictured flying. GETTY IMAGES NORTH AMERICA / MARIO TAMA

"The situation has worsened considerably," Bastian said. "The speed of the demand fall-off is unlike anything we've seen -- and we've seen a lot in our business."

Bastian indicated the company would take more steps in the coming days, saying the "situation is fluid and likely to be getting worse."

The moves come on the heels of steps announced Thursday night by American Airlines, which plans to reduce international capacity by 34 percent.

American said it would continue to operate flights to European cities including Paris and Madrid for seven days and suspend service to other cities on Friday.

The airline will also suspend service to Argentina and reduce service to London, which is outside Trump's European travel ban.

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