EagleTribune.com, North Andover, MA

Whatever the reason, on Sept. 11, 2001, flight attendant Elise O'Kane was prevented from getting on an airplane she had flown nearly every week for three years. Instead of working the morning run from Boston to Los Angeles on United Airlines Flight 175, she boarded a jet that was scheduled to stop in Denver before heading on to Los Angeles.

United 175, the flight she usually worked, was hijacked by terrorists who crashed it into one of New York's twin towers while O'Kane was safely on her way to Denver.

"I'd been flying the Boston-to-L.A. route on Tuesday mornings for several years," said O'Kane, 43, of Atkinson, N.H. "Every September 11 is a bonus that I'm alive. My husband and I usually spend the anniversary of that day in Bethel, Maine. We play golf but avoid television. The church bells in Bethel are enough of a reminder for me."

The events that prevented her from taking her usual flight included a computer error, a scheduling error and O'Kane's unwillingness to bump a junior flight attendant who had been assigned to the flight.

Since the terrorist attacks, O'Kane, a cheery, outgoing woman with sparkling blue-green eyes, has devoted part of her life to helping people close to death. Following 9/11, she returned to flying while vowing to do something that would honor those who were lost in the attacks.

She entered nursing school at Northern Essex Community College in January 2002, returned briefly to the air following her graduation in the spring of 2005, then took a leave of absence for a nursing job at Lowell General Hospital. She started working there in January.

"I'll sit by the bedside of people who are dying and I'll hold their hand," she said. "I won't let them die alone."

Since the day of her missed flight, O'Kane and her husband cherish each day they have been given.

"I no longer question why things happen," O'Kane said. "It doesn't bother me when I miss a highway exit or I lock my keys in my car. I no longer question these things. I figure it must be for a reason."

Her husband, William O'Kane, considers himself a very lucky man.

"I thank God every day. Because of fate, my wife wasn't on that flight," he said. "We appreciate each other a lot more, and we don't take each other for granted."

A New Bedford native, Elise O'Kane's first encounter with the airline industry was when she waitressed at a restaurant while in college. She was serving two personnel representatives from TWA, and they invited her to interview for a flight attendant job - which she got.

Not once, not twice, but three times Elise O'Kane was prevented from taking United Flight 175.

Incident one: Scheduling mistake

On Aug. 17, 2001, O'Kane got online and entered the flights she'd like to be assigned to for the next next month into her computer.

The schedule would have included the familiar Tuesday morning run on United 175 - a flight she enjoyed with a crew she felt comfortable with.

"When the schedules came out and I looked at mine, I said to myself, 'I didn't bid this,'" O'Kane said. "I realized then that I'd transposed a number. It's a mistake I'd never made in nearly 20 years of flying. Looking back, whether it was God or a family member I'd lost, some sort of higher power had intervened. It was definitely intervention."

Incident two: Computer glitch

On the weekend prior to Sept. 11 she tried to swap flights by going online to change her schedule.

"I logged in, hit enter and the computer responded with an error message," she said. "I tried all weekend to change my schedule but I kept getting the same message."

She called the airline's computer systems department.

"They told me, 'We don't know anything about this error message you are talking about,'" she said.

On the night of Sept. 10 she packed her lunch in preparation for her morning flight. On the morning of Sept. 11 she said goodbye to her husband, a sales and marketing manager, and drove to a parking garage in Chelsea.

O'Kane hopped on a shuttle bus, glanced out the window and noticed a young man running toward the bus. She ordered the driver to wait. Robert Flanagan, 33, hopped on and sat next to her.

"He told me how excited he was about the flight," she said. "I told him about the computer error and how he took my flight. He told me about how he wanted to have a Bloody Mary at the Shellback Tavern in L.A. He said they made the best Bloody Marys in the country."

At Logan Airport, O'Kane ran into the crew of United 175.

"They asked why I wasn't with them today," O'Kane said. "I told them they have a great reserve attendant by the name of Robert Flanagan."

Incident three: Didn't want to break his heart

At check-in time, O'Kane could have bumped Flanagan. She was a senior flight attendant and a certified purser. But she didn't want to break the young man's heart.

It was the last time she was ever to see Robert Flanagan or her old crew again.

On the runway, American Flight 11 taxied out, O'Kane's flight was next, followed by United 175. Somewhere between Boston and Denver, O'Kane brought coffee to the pilot and co-pilot and was greeted by flailing arms and disbelief.

"You could hear air traffic controllers on the radio and they were crying," she said. "The look on the pilot's face was one of terror. "I made an announcement that we were to land at the closest airport - which was Detroit."

Back home in Atkinson, William O'Kane watched the horrific scenes on television of planes crashing into the twin towers. He had no idea what flight his wife was on.

When Elise O'Kane finally got off the plane in Detroit, a crying flight agent told her about the attacks.

"My legs gave out and I dropped to the ground," she said. "I was shaking, and my husband didn't know what flight I was on. I called him on the cell phone and we cried."

During her five-day layover, Elise O'Kane thought about why her life was spared and what she would do to honor those who died.

She also vowed to meet Flanagan's family and take the flight the young man never completed.

She took that flight in July 2005, sipped the Bloody Mary that Flanagan never got to drink. One week later O'Kane met Flanagan's family in Philadelphia and told them her story.

"I felt a sense of completion," O'Kane said. "I felt there was a reason why we met at the airport. I told his family about how happy he was to be flying that morning."