The following is an article from USA Today:

Aviation experts cannot explain what has prompted three airline passengers to try to open cabin or cockpit doors while in flight the past few days, but they say other passengers shouldn’t worry.

Exit doors cannot be opened while the plane is in the air, they say, and doors to pilot cockpits have been hardened and locked since the Sept. 11, 2001, terror attacks.

“It’s not possible to open an aircraft door in-flight, and cockpit doors have been reinforced,” says American Airlines spokesman Ed Martelle.

Former Federal Aviation Administration security director Billie Vincent says he has no idea and no theories for “this outbreak of insanity” by passengers.

The latest incident occurred Tuesday night on a flight from Orlando to Boston. Massachusetts police say they arrested 43-year-old Robert Hersey after his alleged attempt to open an emergency door on a Delta Air Lines Airbus A320. Passengers say he had been drinking and appeared upset when the flight was late.

“The report I saw indicated that the Delta passenger was drunk, but why try to open a door in-flight?” Vincent asks.

•On Sunday, American Airlines flight attendants and passengers subdued a Yemeni native who was screaming and pounding on a cockpit door of a Boeing 737-800 jet 40 minutes before it was scheduled to land in San Francisco, says the airline’s spokesman, Ed Martelle.

Police arrested Rageh Al-Murisi, 28, and charged him with interfering with a flight crew. A federal judge on Tuesday denied bail.

Assistant U.S. Attorney Elise Becker says Al-Murisi yelled “God is great” in Arabic before heading to the cockpit.

Martelle says American flight attendants didn’t understand what Al-Murisi was saying in Arabic and initially thought he was mistaking the cockpit door for the bathroom door. When they pointed him to the bathroom door, he again tried to open the cockpit door, Martelle says.

The flight from Chicago was carrying 156 passengers, four flight attendants and two pilots.

•Also on Sunday, Continental Airlines Flight 546 was diverted to St. Louis after a passenger tried to open a cabin door and was subdued by flight attendants and passengers. The Boeing 737-800, carrying 160 passengers and six crewmembers, was en route from Houston to Chicago.

Prosecutors say that Reynel Alcaide, 34, of Burbank, Ill., rushed up the aisle toward the front of the plane, pinned a flight attendant against a wall and tried to open the door.

Passengers shouldn’t be concerned about the rash of incidents because they “are so infrequent,” says Martelle of American.

“The only reason anybody is talking about this is because Osama bin Laden was killed last week,” the airline spokesman says.

According to aircraft manufacturer Boeing, cabin doors “cannot be opened once an airplane is airborne and pressurized.”

Planes are pressurized to the equivalent atmosphere of 8,000 feet to assist passenger breathing and comfort, Boeing’s website says.

“Since airplanes typically cruise above 30,000 feet, the air pressure inside the plane is much greater than the pressure outside — and that pressure differential makes it impossible to open the door,” Boeing’s website says.

Vincent says fliers are aware of security concerns following the death of bin Laden and have become more alert and ready to act to resolve in-flight disturbances since 9/11.

Aviation consultant Michael Boyd, however, says “the most dangerous and amateur concept today is that passengers won’t let another event happen.”

It “is stupid,” he says, to assume that “the next event will be a replay” of what occurred when passengers reportedly fought hijackers before all were killed when their plane crashed near Shanksville, Pa., on Sept. 11, 2001.

(Source: USA Today)