Delta Flight to Boston Makes Emergency Landing in Porto; What Happened? Know All About the US Airline Ranked No. 1 for the 8th Time

Delta Air Lines was recently in the spotlight after a Boston-bound flight from Barcelona was diverted to Porto, Portugal, following a report of smoke in the cabin. The Airbus A330 aircraft landed safely, while several passengers received medical treatment. The incident has again put one of the United States’ largest airlines in the spotlight.

Why is Delta in the news?

Delta flight DL251 was travelling from Barcelona to Boston when the crew reported smoke inside the cabin while flying over the Atlantic. The aircraft diverted to Porto, where emergency services responded after landing. Reports said passengers were treated for possible smoke inhalation, with some taken to hospital. Delta confirmed the aircraft landed safely following a mechanical issue.

The airline has also remained in the news for its large US network, international expansion and industry rankings. Delta operates up to 5,500 daily Delta and Delta Connection flights to more than 300 destinations across six continents, according to company figures.

Where does Delta rank in the US?

Delta is one of the major US legacy carriers, alongside American Airlines and United Airlines. Its exact ranking depends on the metric used, such as passengers, revenue, fleet size or available seat miles.

In 2026, Delta was ranked No. 1 among US airlines by The Points Guy for the eighth consecutive year. Delta also said it was the only airline in TIME's 2026 list of America's Best Companies top 100, where it ranked No. 98 overall.

When was Delta founded?

Delta's origins date to 1925, when Huff Daland Dusters was established in Macon, Georgia, as an agricultural aviation company specialising in crop dusting. The company later moved to Monroe, Louisiana.

In 1928, C.E. Woolman led a group that acquired the company. It was renamed Delta Air Service, reflecting the Mississippi Delta region it served. Delta was incorporated on December 3, 1928. Woolman is regarded by Delta as the principal founder of the airline that eventually became Delta Air Lines.

From crop dusting to global airline

Delta operated its first passenger flight in 1929 between Dallas, Texas, and Jackson, Mississippi, with intermediate stops. Passenger services expanded over subsequent years, and the company eventually developed into a major US carrier.

Delta's headquarters moved from Monroe to Atlanta in 1941. Today, Atlanta remains its headquarters and largest hub. The airline is also a founding member of the SkyTeam global alliance.

With about 100,000 employees and more than 200 million customers served in 2025, Delta has evolved from an agricultural aviation company into a major global airline.