On Sunday, a JetBlue plane from Las Vegas to New York, Flight 194, had to make an emergency landing because the plane’s hydraulic system failed. According to ABC News, the aircraft returned to the Las Vegas airport after approximately four hours.

The New York Post reports that the pilots radioed to air traffic control and said that they were having issues with “quite a few things, but the initial thing is . . . we’ve lost two hydraulic systems.”

The hydraulic systems are important because hydraulic pressure powers most of the plane's mechanical controls. Most planes have 2 or 3 redundant hydraulic systems. When those systems failed, the aircraft began to lurch sideways and make steep turns. "The plane kind of felt out of control. It wasn’t able to balance itself, and the air was choppy," said passenger Travis McGhie.

The motions affected some of the passengers. Another passenger on the flight, Tom Mizer, told the Post, "People were getting sick. Some people were throwing up. There were a lot of people getting nauseous." In addition to unpleasant physical effects, the unsteady plane impacted people emotionally. "People on board got a little freaked," Mizer said. "People were upset. Nobody was crazy, but everyone was upset."

It took a while for the plane to land because that model aircraft, an A320 Airbus, cannot dump its fuel. The pilots had to fly in circles over Las Vegas until they'd used enough fuel for the plane to land safely. Upon landing, the airplane was towed to the gate because one of the wheels wasn't working.

Flight attendants tried to keep passengers calm. One woman kept a smile on her face and told passengers that she wasn't scared, and they had no reason to be afraid, either. In a statement, JetBlue said, "The actions the crew took in response to this event truly represent who we are and our core value -- safety."