The airlift was fraught with risk from the start. Donors from Silicon Valley including LinkedIn co-founder Reid Hoffman, as well as Facebook Inc., had agreed to fund an evacuation flight for 188 journalists, aid workers and others who were suddenly in danger after the Taliban’s quick capture of Kabul. They hoped to get most of those evacuees to Mexico City, via Abu Dhabi, to start a new life.

Those plans largely succeeded. But amid the chaos in Afghanistan, they also took an unexpected turn.

Shortly before their flight left on August 30, the airline — Kam Air — stuffed the half-empty plane with at least 155 additional passengers — its employees, their families and more, according to US officials and organisers of the flight.

The 11th-hour surprise created agita at the State Department and in the United Arab Emirates because the extra passengers — who weren’t on the plane’s manifest — hadn’t been screened for that flight and raised security and immigration concerns. It also created angst among many of the organisers and financial supporters, who say they had carefully vetted the original list of passengers and weren’t aware of the extra passengers until the plane landed in Abu Dhabi.

“The 155, not on the FB manifest, were placed on the FB airplane by KAM airlines,” according to a State Department email obtained by Bloomberg News. “FB (and everyone else) learned about these individuals when they landed in Abu Dhabi.”

The circumstances surrounding their departure underscored the turmoil that followed the US withdrawal from the longest foreign war in American history and the difficulty of controlling events in a war-torn country from halfway around the world. But it also exemplified the ways strange bedfellows — in this case, Facebook Inc., a prominent tech founder, security firms, consultants and aid agencies — came together to spirit endangered people out of Afghanistan.

A representative for Kam Air didn’t respond to requests for comment.

Most of the original group of 188 evacuees made it to Mexico, transferring in Abu Dhabi to an EgyptAir flight that continued on to Mexico City via Cairo. The Kam Air employees and other last-minute additions to the Facebook flight remain in the UAE, where they are being vetted with other evacuees, according to administration officials.

In a September 20 situation report, US diplomats stationed in Abu Dhabi said their post still “awaits guidance” on about 3,600 evacuees in the UAE — many of whom escaped thanks to help from outside private groups — “who are not confirmed as belonging to priority categories” such as US citizens or people in immediate danger.

At a September 8 press conference, Secretary of State Antony Blinken praised charitable organisations and others that were working to evacuate people from Afghanistan. But he said such privately-founded airlifts create challenges with US personnel on the ground or normal security procedures. “Some of the groups claiming to have all the documentations and arrangements locked down unfortunately don’t,” he said.

While the Facebook flight has been reported previously, Bloomberg News has uncovered new details about it from those on board and others involved in planning the privately funded evacuation, including the involvement of Hoffman, the harrowing days and hours before takeoff, and the unexpected addition of nearly twice as many passengers.

Eric Montalvo, a lawyer and former US Marine who helped arrange the flights, was unapologetic for the way the flight transpired, saying the plane had extra room for people whose lives were in danger if they remained in the country. “Extra lives being saved should never be associated with a complaint,” Montalvo said. “Life is precious. One cannot create the circumstances for failure and then blame the victims of that failure for their desire to survive.”

The operation was organized by a private, Kirkland, Washington-based security firm called Concentric, with help from Facebook, Montalvo, Amman, Jordan-based Magenta Consulting, and nongovernmental organizations in the U.S. and elsewhere. Their evacuees were Afghan nationals and included at least 75 children, about 30 people affiliated with Facebook such as employees and their families, as well as aid workers, journalists and even a comedian. All of them were at risk of retaliation by the Taliban for their work if they remained in the country.

Those evacuees were all on the manifest and the UAE knew they were coming, according to the organizers.

“I went out into the private donor network of people that were interested in this and once we had formulated a plan we raised almost a million dollars in 24 hours,” said Roderick Jones, Concentric’s executive chairman. “I’ve always felt there was a moment where you can put private capital and donor money to work where markets or governments can’t find solutions. And it turned out this way because we could take the risks, and we could do this thing in the middle.”

In a statement Facebook said, “In the process of assisting Facebook employees and close partners to leave Afghanistan, we joined an effort to help a group of journalists and their families who were in grave danger. Thanks to the leadership of the Mexican government and the support of the UAE in providing the initial landing, the journalists have been welcomed in Mexico.”

Hoffman was among the first to fund the effort, according to his philanthropic advisor Dmitri Mehlhorn, who was responding on Hoffman’s behalf. He donated money for two other evacuation flights as well as support for Afghans upon arrival at their destinations, Mehlhorn said. Other tech entrepreneurs donated to the operation, according to Concentric, but their identities couldn’t be confirmed.