"There was a man who was kind of clawing at the exit doors," passenger Arthur Berry of Portland said.
Investigators say a man, who was possibly having a seizure, tried to open the cabin door of the plane which had about 50 passengers onboard.
Arthur and Beverly Berry who saw the man's dangerous actions play out say a flight attendant immediately restrained him.
He put the dazed and confused man in the back of the plane, but he jumped up one more time and headed for the door again.
"Very nice appearing man, he looked very clean cut, but his eyes didn't have a good look," Beverly Berry said.
The flight which left Portland at 3:57 p.m. was over northeastern Connecticut when the plane was diverted to Boston.
Within minutes of the emergency, pilots were able to land at Logan International Airport where Massachusetts State Police and federal investigators were waiting to take the passenger into custody.
"He didn't seem like someone who was trying to cause harm; it seemed like somebody perhaps who decided mid-flight that he needed to leave," Rob Gips of Portland said.
The suspect, identified as 40-year-old Michael Ensalaco, has been charged with interfering with a flight crew.
He was traveling on business and had a quick layover in Philadelphia before returning to his hometown just outside Charlotte, North Carolina.
Amee Downing, who answered a phone call by the Associated Press to Ensalaco's Charlotte-area home and said she was a neighbor speaking for his family, said he has had seizures before.
"This is the first time this has ever happened when he's been traveling on business," Downing said.
She said Ensalaco works in the food service industry and was headed home from a business trip.
Since investigators had to interview the crew in Boston, the U.S. Air flight was cancelled to Philadelphia.
Passengers were able to jump onto other flights, but they had quite a delay.
