A Delta Air Lines flight carrying 181 passengers made an emergency return to Atlanta's Hartsfield-Jackson International Airport Thursday morning after crew members detected a smoky odor onboard, and the airline still hasn't said what caused it.

Delta Flight 1334 lifted off around 7 a.m. bound for Fort Lauderdale. Minutes later, the captain reversed course and brought the aircraft back to the same gate it had just left. No injuries were reported, and Delta said the plane "landed normally without incident."

But 181 passengers sat through an unscheduled return to the tarmac with no clear explanation for the smell that cut their trip short. The airline has not disclosed the source of the odor, and no word has come on whether federal regulators are looking into the incident.

Crew halted the climb at under 6,000 feet

Flight tracking data showed the crew stopped the plane's ascent at roughly 5,900 feet before turning back. The New York Post reported that FOX 5 Atlanta identified the smoky smell as wafting from the cockpit, a detail Delta's own statement did not confirm or deny.

Delta released a statement after the landing:

"Delta flight 1334 safely returned to Atlanta shortly after departure out of an abundance of caution after a smoky odor was reported onboard. The flight crew followed established procedures, and the aircraft landed normally without incident."

The airline added a second line aimed at the stranded passengers:

"Nothing is more important than the safety of our customers and crew, and we apologize to our customers for the delay in their travels."

Passengers left waiting with few answers

After the plane returned, flight tracking showed the rescheduled departure running about two and a half hours behind the original. Delta did not say whether any of the 181 passengers or crew members were evaluated by medical personnel on the ground.

The airline also left open the question of whether the FAA or the National Transportation Safety Board had been notified. Neither agency was mentioned in Delta's public statement, and no regulatory response has been disclosed.

For the passengers who boarded a routine morning flight to South Florida, the episode amounted to a sudden reversal, a smoky cabin, and a corporate apology, but no explanation of what went wrong or whether the aircraft had a mechanical problem that could recur.

When an airline tells you "nothing is more important than safety," the least it can do is tell you what threatened it.