Updated

A Sept. 11 widow who lost her husband in the World Trade Center was among those who perished aboard a commuter flight that crashed into a house in Buffalo, N.Y.

Beverly Eckert of Stamford, Conn., whose husband Sean Rooney died in the 2001 attacks, was one of the 50 victims of the Continental Flight 3407 accident.

Her sister Sue Bourque was at the Buffalo airport awaiting official confirmation that Eckert had been on board. Officials investigating the crash have not yet confirmed Eckert was among the 44 passengers killed Thursday night.

"We know she was on that plane," Bourque told the Buffalo News, "and now she's with him."

Eckert and Rooney were high school sweethearts. She had continued to live in the couple's home in Stamford after he died more than seven years ago.

She was flying to her hometown Thursday night when the plane crashed on approach to the Buffalo airport. She had planned to celebrate Rooney's 58th birthday.

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The commuter prop jet was heading to Buffalo from Newark, N.J., and was attempting to land in foggy, snowy weather when air traffic control lost contact with it about 10:20 p.m. The plane dove into a house in a Buffalo suburb, killing all 49 on board and 1 person in the home.

Eckert became a tireless activist after Sept. 11, 2001, for a country safer from terrorism.

Just last week she was at the White House with President Obama, part of a meeting he had with relatives of those killed in the 2001 attacks and the bombing of the USS Cole to discuss how the new administration would handle terror suspects.

Obama paid tribute to Eckert in remarks before the Business Council on Friday at the White House.

"Keeping with that passionate commitment, she was on her way to Buffalo to honor her husband's birthday," Obama said. "I pray that her family finds peace and comfort in the days ahead."

Another 9/11 family activist, Mary Fetchet, learned Eckert was aboard the plane from another close Eckert family friend now headed to Buffalo.

"She was such an important part of all of our work," Fetchet said.

Eckert was one of the most visible faces in the aftermath of the terror attacks, becoming co-chairwoman of the victims group Voices of Sept. 11.

The organization, made up of Sept. 11 widows, mothers, and children who became amateur lobbyists, ultimately forced lawmakers in 2004 to pass sweeping reforms of the U.S. intelligence laws. They spent months walking the halls of Congress.

Eckert openly expressed her grief.

She cried as she told the story about how Rooney was on the phone in the World Trade Center saying he loved her when suddenly there was a loud explosion and nothing more.

And she wept before Congress as she tried to push the government do a better job protecting its citizens from terrorism.

When it was over and they'd won passage of the intelligence reform law, Eckert vowed to quit her high-profile role "cold turkey." All she wanted, she said, was to go home, buy groceries and return to something resembling a regular life.

"I did all of this for Sean's memory, I did it for him," she said tearfully. "There is a euphoria in knowing that we reached the top of the hill. ... I just wanted Sean to come home from work. Maybe now, someone else's Sean will get to come home."

After the 2001 attacks, she co-chaired the 9/11 Family Steering Committee, a group of activists devoted to exposing government failures that led up to the 2001 attacks, and fixing them.

She pushed for a 9/11 Commission. She pushed the Bush administration to provide more information to the commission. And when the commission's work was over, she pushed Congress to adopt their recommendations.

It was not an easy role for her.

One night after a long day before Congress, she found herself in the New York City train station, without a connecting train to her Connecticut home.

"We slept in the train station. We had no place else to go. That's when you look at yourself and say, 'What am I doing? How can we possibly get this done?'"

After the law passed, Eckert turned her energies to Habitat for Humanity, helping build homes for low-income families.

"I'm in shock, I just can't believe it," said Carie Lemack, whose mother died Sept. 11 on one of the hijacked planes. "Beverly had a can-do attitude about everything, and she never gave up."

Click here to read more on this story from the Buffalo News.

The Associated Press contributed to this report.