The big four US airlines shed another $5 billion in market cap this week

Shares of the big four US airlines — Delta Air Lines, American Airlines, United Airlines, and Southwest Airlines — are wrapping up yet another bleak week amid a host of challenging factors for the aviation industry.

From Monday, March 24, through midday Friday, March 28, Delta and United shares have fallen more than 8%, American shares more than 7%, and Southwest’s more than 3%.

The sell-off represents a loss of $4.8 billion in market cap for the carriers, which with their regional partners control 80% of the US market.

March, and 2025 in general, have not been kind to aviation companies. The S&P Composite 1500 Passenger Airlines index had its worst week since the peak of the pandemic in 2022 earlier this month and is down 22% on the year. So far in 2025, the big four have collectively lost more than $24 billion in market cap — roughly the cost of 180 737 Max 10s.

A familiar batch of issues is still causing the turbulence: tariffs, tariff-impacted travel, tariff-impacted consumer spending, and general safety fears.

25% tariffs on steel and aluminum (metals that planes are made of) went into effect March 12. It’s estimated those tariffs could hike the production cost of a narrow-body aircraft by up to $2.5 million.

A slew of other broad tariffs on goods from Canada, Mexico, China, and Europe have also played a major role in the downturn, in addition to a shift away from momentum stocks that has gut-punched the market in recent weeks. Consumer confidence reached a four-year low this month, and air travel between the US and Canada has plunged as much as 76%. Delta, American, JetBlue, and a few smaller airlines have scaled back their capacity for the quarter April through June.

Repeated safety incidents and close calls in the last few months also might have consumers choosing travel options that stay on the ground. Data from Amanda Demanda Law Group shows that online searches for “are planes safe now?” were up 900% in February.