Delta Air Lines on Monday cut its financial forecast for the first three months of the year, saying that growing economic concerns among businesses and consumers had lowered demand for domestic travel.

The airline’s warning was the latest sign that the U.S. economy, or at least perceptions of it, have been weakening in part because of changes in federal policies announced by President Trump.

Delta said it now expected quarterly revenue to rise by at least 3 percent from a year ago, down from a minimum gain of 7 percent it had projected just two months earlier. Delta’s share price, which fell more than 5 percent in regular trading on Monday, tumbled an additional 12 percent in extended trading after it published the update.

“The outlook has been impacted by the recent reduction in consumer and corporate confidence caused by increased macro uncertainty, driving softness in domestic demand,” the airline said in a securities filing. The airline published the update alongside a presentation it plans to deliver on Tuesday at the J.P. Morgan Industrials Conference.

In addition to the weakened confidence, Delta said fewer passengers were booking flights on short notice. But it added that its expectations for revenue growth from high-end travel, international flying and loyalty programs were unchanged.

The bad news was not a complete surprise. One financial analyst, Savanthi Syth of Raymond James, said in a note last week that the airline had probably lost some momentum in February from a slowdown in government travel, bad weather and customer anxiety after an airplane operated by a Delta subsidiary flipped after landing in Toronto.

Still, Ms. Syth said that demand for flights over spring break appeared to remain strong and that other airlines had not been able to make gains at Delta’s expense.

While some airlines have faced a variety of challenges recently, Delta and a few others have benefited from strong demand for premium airplane seats and international flights.

Delta said in January that it had collected more than $15.5 billion in revenue in the final three months of last year, a record. At the time, its chief executive, Ed Bastian, said Delta was on track to “deliver the best financial year in Delta’s 100-year history.” Last month, it said employees would receive an average of five weeks of pay in profit-sharing.

But economic fears have started to grow in recent weeks amid fears of a trade war. Wall Street had its worst day of the year on Monday after Mr. Trump refused to rule out the possibility that his policies would cause a recession.

Other large carriers, including American Airlines, United Airlines and Southwest Airlines, are also scheduled to present updates at the J.P. Morgan conference on Tuesday.