Passenger Pleads Not Guilty to Trying to Open Jetliner Door in Midflight

May 11, 2011— -- A man arrested for allegedly trying to yank open the emergency door of a Delta airlines passenger jet in midflight pleaded not guilty in court today and later said it was a "big misunderstanding."

Robert Hersey, 34, of Arlington, Mass., was arraigned in a Boston court Wednesday for allegedly trying to open an emergency door while Delta flight 1102 was en route from Orlando to Boston Tuesday night. He pleaded not guilty to charges of interfering with a flight crew.

Hersey's attorney Ron Wayland said he was released on $1,000 cash bail, pending a pre-trail hearing on June 6. Judge Roberto Ronquillo Jr. ordered Hersey to stay alcohol-free while the case is pending.

The incident was the fourth mid-flight scare in three days, although they do not appear to be related or to involve terrorism.

Hersey told ABC's Boston affiliate WCVB that the entire episode was a "big misunderstanding." Witnesses have claimed that Hersey was intoxicated at the time, but he told the station that he was not inebriated, having only had a few beers and a hamburger before boarding.

Hersey was sitting in the exit row and allegedly grabbed the handle of the emergency door and tried to open it. Differences in air pressure prevented the door from being opened midflight, but his actions set off an alarm and scared passengers.

The Transportation Safety Administration said Hersey was subdued by two other passengers, one of whom was an off-duty police officer. The flight, carrying 148 passengers, landed in Boston without further disruptions.

"When we pulled in, six troopers, some of the biggest guys I've ever seen in my life went streaming to the back," said passenger Todd Varley. Varley told WCVB that once subdued, the suspect was placed in between two passengers so he could not move.

Wayland told ABC News that Hersey was cooperative with flight attendants and denied that he was unruly during the flight. He said that a casing on the exit door handle fell off, which set off the alarm.

Hersey's arrest was the latest incident to in a series that have made airline passengers jittery.

This past Sunday, a man tried to open the door on a Continental Flight from Houston to Chicago. It was diverted to St. Louis.

That same day another Delta flight to San Diego diverted to Albuquerque after a flight attendant found a napkin with the word bomb written on it in the plane's bathroom. The passengers and luggage were rescreened.

Then on Monday, perhaps the most unsettling incident occurred when Yemeni national Rageh al Murisi allegedly tried to enter the cockpit of San Francisco bound American Airlines flight 1561.

A recording provided by LiveATC.net of the plane's radio transmissions with air traffic controllers revealed the drama. "We are going to need priority handling on our arrival," the pilot is heard saying. "Had a passenger conflict here."

Police say he rammed the door with his shoulder while shouting "allah akbar," or God is great. Passengers subdued him. Now he is being held without bail. Sources told ABC News that officials do not believe he was a terrorist but are investigating his background as a precaution.

ABC News' Pierre Thomas contributed to this report