Keep your tray tables in their upright and locked positions because you never know when an unruly passenger or an unconscious pilot will hasten your flight into an undesirable descent.

Two airplanes needed to make emergency landings Thursday after midair mishaps threatened to upend the flights into tragic turbulence. In one instance, a pilot passed out in the aisle when he was supposed to be steering in the cockpit.

In the other, an unruly passenger was so disruptive it forced JetBlue Airways Flight 185 from New York to San Diego to land in Denver, the airline confirmed.

The unidentified woman became enraged when another passenger was moved to an open seat next to her, according to a fellow passenger.

The upgrade angered the irritable lady because he was not required to pay the same premium price that she had.

So the woman allegedly started arguing with the flight crew and verbally abusing the male passenger until a federal air marshal intervened, as fellow passengers recorded the heated quarrel with their smartphones.

“She got mad about like leg space or something,” one passenger told ABC-affiliate KMGH. “I don’t really know but she like went crazy and started screaming. It was an adventure.”

The pilot unexpectedly landed the plane at Denver International Airport around 7:15 p.m. Thursday, reported the Denver Post.

The disruptive passenger was escorted off the plane and handed over to the police. But neither the male passenger nor Jet Blue wanted to press charges, so authorities refrained from charging the woman with the federal offense of interfering with a flight crew or the misdemeanor of disturbing the peace.

Shortly before the passengers reboarded Flight 185 to continue to San Diego around 9:30 p.m., an unrelated airborne spectacle sparked the second emergency landing.

The pilot of Alaska Airlines Flight 473 from Los Angeles to Seattle opened the cabin door and collapsed in the aisle in front of passengers, Portland-based KATU reported.

“The flight attendant was going up and down the aisle saying ‘are there any paramedics, doctors, nurses — someone who can come help?'” one passenger said explained.

The co-pilot took control of the aircraft and safely returned the plane’s 116 passengers and five crew members to the ground with an emergency landing at Portland International Airport just after 9 p.m. local time, according to Alaska Airlines.

An ambulance took the pilot, who has been flying with the airline for 28 years, to a nearby hospital. A spokesman for the airline said the pilot suffered from a medical condition but, citing company policy, declined to be specific.

Another flight crew arrived and brought the passengers to Seattle on the same plane overnight, reported ABC News.

– NY Daily News