70 years after the first attack on a U.S. commercial airliner, there’s a memorial

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A granite marker lists all 44 people killed in the attack on Flight 629. Seals of agencies that responded to the disaster are also featured beneath an outline of an airplane.
Courtesy Denver Police Museum
70 years after the bombing of United Flight 629, this marker will be placed at the foot of Denver's former control tower.

In the middle of the night on November 1, 1955, an adolescent Susan Morgan was roused from a deep sleep and told her parents had been in a plane crash. Back when individual aircraft had names, Mainliner Denver blew apart shortly after takeoff from Stapleton Airfield. Stewart and Anne Morgan were among the 44 who perished.

“A lot of my thoughts initially were just stunned sleepiness from a 12-year-old,” Susan Morgan recalled of that night seven decades ago. “The next week was spent with strangers arriving at the house. They all brought their casseroles and talk of God,” Morgan added. Her parents had not been religious.

Twenty-five sticks of dynamite, wrapped as a Christmas gift, created a fireball in the sky east of Longmont. The woman who brought the lethal package aboard was ignorant of its contents. Her disgruntled son gave it to her after buying a life insurance policy for her at the airport, a common offering at the time.

There has never been a proper memorial to the victims. Until now.

“This is long overdue,” said Michael Hesse, president of the Denver Police Museum. He helped advocate for a marker that names the passengers, crew, and acknowledges the many first responders. It will be unveiled Saturday at the base of the former control tower in the neighborhood now known as Central Park.

20251028-STAPLETON-AIRPORT-CRASH-MEMORIAL
Ryan Warner/CPR News
Michael Hesse, president of The Denver Police Museum, helped create a Flight 629 memorial.

“It is made of granite and engraved with the front and tail of an aircraft,” Hesse said. “The FBI (which helped in the investigation) headquarters is just a block away. United’s training center is blocks away. It will provide an opportunity for both of those organizations to share their history.”

Susan Morgan will attend the unveiling, but said the marker won’t matter to her as much as the company of other families whose lives were upended.

“I’m going to see other people who were affected by it, which has never happened to me,” she reflected. “Maybe what I’m going to be able to feel is a little bit of belonging, and that would be nice. That would be really special for me.”

black and white photo of a crowd standing around a plane crash
Courtesy of Longmont Museum
A crowd is seen around the tail section of United Flight 629, which was bombed shortly after taking off from Denver in 1955.

The sabotage of United flight 629 came before airport security screening, before there was an agency dedicated to investigating air disasters, and before laws were on the books making such an attack a crime.

The perpetrator, 23-year-old John Gilbert Graham, was convicted of a single state murder charge for killing his mother, Daisie King. In 1957, he was executed in Colorado’s gas chamber.

Want to learn more about this case? We found attorney Andrew J. Field’s 2005 book “Mainliner Denver” very helpful. Also, the top of the old control tower, now FlyteCo Tower, has become a museum. Tour guide Sean Henson is well-versed in Stapleton Airport history.