Emergency Landing Delta Air Lines - A Delta Air Lines flight heading from Minneapolis to Las Vegas made a quick "roller coaster" descent Thursday after the pilot was locked out of the cockpit, according to ABC News. United flight 1181 reportedly descended into Ontario International Airport at about 9 a.m. when it made the emergency landing, the Federal Aviation Administration and a passenger's account said.

The cockpit door reportedly malfunctioned, locked the pilot out of the cockpit, resulting in the emergency landing, airport officials told KTNV.

"About half way through [the 2.5-hour flight] there seemed to be some talking at the front of the plane. You could see the captain out there," passenger Jesse Dougherty told ABC News about the emergency ladning. "There wasn't a huge panic but some confusion."

Dougherty said the captain explained to the passengers that the door was jammed, therefore he couldn't get back into the captain.

"It was very, very bizarre," added Dougherty.

As the first officer made the emergency landing "perfectly," all passengers made spontaneous applause.

"The flight landed safely after diverting to Ontario, California, due to reports of a burning smell," said a statement released by United on the emergency landing.

The pilot who successfully made the emergency landing was identified as 51-year-old Christopher Okechukwu of Paramus. He safely landed the Cessna C150 on Route 23 near Paradise and Doremus roads in West Milford around 1 p.m., said police and federal officials. Okechukwu was reportedly the only person on the plane.

All of the 199 passengers and seven crew members aboard the Boeing 757 are safe. Maintenance crews are now working to review the aircraft, "working as quickly as possible to get our customers to Washington, D.C."

Also, there were no vehicles hit during the emergency landing, according to NBC New York.

A passenger tweeted and described light smoke in the cabin after the plane made the emergency landing. There was also reportedly a flurry of firefighter activity around the plane once it stopped on the Tarmac, reports NBC Los Angeles.

"25,000 feet to 0 in 5 minutes. A roller coaster!" Mitchell Hashimoto tweeted under the handle @mitchellh. However, the tweet about the emergency landing has now been deleted.

Another passenger tweeted that they were being evacuated from the plane in Ontario.

"This is crazy," said William Mayer, who tweeted as @cigarash.

The plane's flight path was posted on a flight-tracking website. It reportedly showed the plane circling back to the LA area soon after taking off from LAX. The plane never made it any further than about Palm Springs.

The emergency landing is now being investigated by the FAA.