CHICAGO, March 10 (Reuters) -

Delta Air Lines ( DAL ) on Monday slashed its first-quarter

profit estimates by half, sending its shares down 14% in

aftermarket action, with its CEO saying shortly after that the

environment had weakened due to U.S. economic uncertainty.

The Atlanta-based airline is the first major U.S.

carrier to report that mounting economic worries among consumers

and businesses are hurting domestic travel.

"We saw companies start to pull back. Corporate spending

started to stall," CEO Ed Bastian told CNBC. "Consumers in a

discretionary business do not like uncertainty."

U.S.

consumer

and

business confidence

has weakened in the wake of President Donald Trump's

tariffs and threats of additional levies, and raised concerns

about higher prices. The Atlanta Federal Reserve's closely

followed GDPNow tracker suggests the economy could shrink in the

first three months of the year.

Since travel spending closely tracks broader economic

activity, investors and analysts say a downturn would spell

trouble for the airline industry. Carriers' revenue from

government has already taken a hit due to a crackdown on federal

spending.

Delta now expects a profit in the range of 30 cents to 50

cents a share, compared with previous estimates of 70 cents to

$1 estimated in January.

Airline stocks, already hit by the broad selloff on

Monday, were routed in after-hours action. Delta shares lost

14%, while United fell 11%, and American Airlines

dropped nearly 9%.

The S&P 500 passenger airlines index has

fallen 22% in the past month, compared with a 7.5% decline in

the S&P 500 index. Delta's shares have declined 24% in

the last month.

Analysts and investors were Delta's more affluent and

diversified customer base meant it was better-positioned to deal

with weaker demand. But Bastian said the company was seeing

softness in booking from the aerospace and defense, autos,

media, entertainment and tech industries.

Investors and analysts are expecting similar revisions

from other airlines. Several carriers will make presentations on

Tuesday at a JPMorgan industry conference.

Delta said it now expects annual revenue growth of 3% to

4% in the March quarter, lower than an increase of 7% to 9%

expected earlier.

A key economic adviser to Trump on Monday pushed back on

talk of recession, saying there were many reasons to be bullish

about the U.S. economy. But a report from the Federal Reserve

Bank of New York on Monday showed American households growing

more pessimistic about their prospects.