NEW YORK — Minutes after a JetBlue flight took off from New York for Las Vegas, the pilot began muttering things that didn’t make sense to his co-pilot. He started talking about the need to “focus,” lamented that “things just don’t matter,” and yelled at air traffic controllers to keep quiet.

At some point, Capt. Clayton Osbon purportedly told his first officer that “we’re not going to Las Vegas” and launched into a sermon. That set off a chain of events that culminated in a federal charge of interfering with a flight crew being filed against Osbon on Wednesday, a day after he was tackled by passengers at 35,000 feet and later carried off to a hospital.

The Justice Department detailed the allegations against Osbon, 49, in a complaint that indicated Tuesday’s Flight 191 went awry quickly. According to the document, based on an investigator’s interviews with the co-pilot and other crew members, Osbon showed up for the morning flight later than usual and missed the usual preflight crew briefing. But Osbon “initially did not exhibit any bizarre behavior,” the complaint said.

That changed quickly, as the jet was climbing out of John F. Kennedy International Airport. According to the first officer, who was not named, Osbon began speaking incoherently and became increasingly agitated as the flight went on.

After yelling at air traffic controllers, he turned off the radios in the Airbus 320, which had more than 130 people on board, and “sternly admonished the FO [first officer] for trying to talk on the radio.”

“The FO became really worried when Osbon said, ‘We need to take a leap of faith,’ ” investigators said.

Initial reports after the jet made an emergency landing in Amarillo, Texas, said the co-pilot had tricked Osbon into leaving the cockpit by suggesting he use the bathroom. The complaint says Osbon bolted out of the cockpit on his own and headed for the bathroom, alarming crew members. This was about 3 1/2 hours into the five-hour flight.

In the ensuing melee, Osbon reportedly “aggressively grabbed” a flight attendant’s hands; banged on the bathroom door and yelled at a woman inside to get out; yelled at passengers; and pounded so hard on the locked cockpit door that the first officer feared Osbon was breaking through the bulletproof barrier.

By this time, flight attendants had alerted passengers that they might need assistance restraining Osbon, and several of the people on board joined them in pinning him to the ground and holding him there for at least 20 minutes while the flight landed in Texas. The FBI, which is leading the investigation, said Osbon remained hospitalized in Amarillo on Wednesday.

According to the U.S. attorney’s office in the northern district of Texas, a charge of interfering with a flight crew carries a penalty of up to 20 years in prison and a $250,000 fine. Kathy Colvin, a Dallas-based spokeswoman for the U.S. attorney’s office, said no date had been set for a court appearance.

The complaint came hours after JetBlue announced that Osbon, a 12-year veteran of the airline, had been suspended and as passengers who had been on the flight described their shock at the strange event, which many captured on video and posted on YouTube.

“It was surreal. It was like a movie. It really was,” said one passenger, Charlie Restivo.

Those who know Osbon, who lives in Georgia but rents an apartment in the New York City borough of Queens to use before and after flights, said they were stunned. His landlord, Wanda Serra, broke down in tears when told of Osbon’s rant. “I feel like he’s a son,” she told ABC, describing him as a “beautiful man.”

Others in the neighborhood who know Osbon agreed, saying he appeared to be a contented family man.

“Things happen, but I would never have expected it from a guy like that. Something got to him,” said John Morganti.

It was the second incident this month involving an in-flight meltdown by an airline employee. On March 9, an American Airlines jet returned to the gate in Dallas after an attendant let out a bloodcurdling scream and began ranting about a crash as the plane prepared to take off.

In 2010, JetBlue flight attendant Steven Slater gained folk-hero status after he cussed out a passenger while the plane was on a runway in New York, then grabbed a beer, deployed an emergency chute, and slid down it. He was arrested and charged with criminal mischief and reckless endangerment. Slater, who left JetBlue, later apologized, blaming his rant on stress, and paid restitution after pleading guilty to lesser charges.

tina.susman@latimes.com

Richard A. Serrano in the Washington bureau and Molly Hennessy-Fiske in Houston contributed to this report.