Passengers have spoken of their horror after their flight from Las Vegas was turned into a "vomitorium" following a hydraulic failure.

One of the 155 passengers on JetBlue Flight 194 to New York said the plane continuously lurched from side to side and went into steep turns.

Another passenger said people became sick onboard and began to vomit from the motions of the plane.

"People were getting sick. Some people were throwing up. There were a lot of people getting nauseous," Tom Mizer told the New York Post.

Travis McGhie, another passenger on the flight, said to the Daily Mail: "It was four hours of hell."

The AirBus A320 suffered hydraulic failure shortly after takeoff from McCarran Airport in Las Vegas.

Mizer said: "You could hear a screeching - an obvious mechanical screeching. We were bouncing around a lot."

The captain declared an emergency and told air traffic controllers the flight had lost two hydraulic systems.

The plane carried enough fuel for five hours, which could not be dumped, according to reports. The flight had to circle the airport for nearly four hours until it had burned enough to land safely.

Mizer told the Post that the flight crew did everything they could to prevent panic, with one attendant walking down the aisles to reassure people.

"She said 'Look at me, I'm smiling. If I was scared, you would know it. If I'm not scared, you don't need to be.'"

The plane had to be towed to the gate because the front wheels had stopped working.

Political commentator Sarah Elizabeth Cupp described the experience on Twitter.

"Well, after flying for five hours, I've just landed in Vegas. Where I started. Emergency landing after losing hydraulics. The plane turned into a vomitorium. For five hours. And, after all that, I'm still in Vegas," she wrote.

"If I didn't have to get home, I would never fly again."

JetBlue said in a statement that another plane was made available to customers.

"JetBlue takes all incidences seriously, and the safety of our customers and crew members is our No. 1 priority. The actions the crew took in response to this event truly represent who we are and our core value - safety."

The Federal Aviation Administration has launched an investigation into the incident.

- © Fairfax NZ News