CNN  — 

When an advance staffer for Vice President Mike Pence stepped to the podium at an addiction recovery center in New Hampshire on Tuesday morning, the update he delivered didn’t sound good.

“I do have some bad news at this point,” he said seriously. “Air Force Two was headed this way, there’s been an emergency.”

With that, a scramble ensued among the White House, the vice president’s office and a confused public as to what, precisely, was happening, with thoughts immediately turning to a medical crisis or foreign calamity.

It was neither, Pence’s office later announced, declaring the schedule change had nothing to do with his (or President Donald Trump’s) health nor national security. In fact, the vice president’s plane had never left the ground. Without saying what specifically caused him to scrap his planned remarks on the opioid crisis, Pence’s office insisted there was “no cause for alarm.”

One person familiar with the cancellation described it as a site issue, but didn’t specify what the issue was. Another said there was a problem surrounding the event and clearing one or more of the people involved.

Still, the abrupt change did prompt a last-minute scramble – and caused complaints among staffers about how the situation was handled.

Pence boarded his helicopter at the Naval Observatory, his official residence, on Tuesday morning and headed for Joint Base Andrews outside Washington. He was scheduled to take off around 10:15 a.m. ET and touch down at the Manchester-Boston Regional Airport 70 minutes later, where he would then travel in a motorcade to meet former patients and make remarks on opioids at the Granite Recovery Center.

But Air Force Two never took off.

As the plane was idling on the tarmac with staff and the vice president on board, the trip was suddenly scrapped, though aides back at the White House weren’t immediately informed.

Instead, reporters found out after the volunteer staffer in Salem, New Hampshire – where the Granite Recovery Center is located – announced the vice president wouldn’t be coming after all.

“We’ll just ask that you all calmly go ahead and have all of you leave the room,” the staffer told the crowd, according to video posted online.

Canceling a trip moments before a presidential aircraft is scheduled to depart is rare. It was so unexpected that Secret Service agents had to scramble to send Pence’s motorcade to the airport so he could get to the White House.

Vice presidents do not traditionally land aircraft on the South Lawn of the White House, so using the helicopter to return to Washington wasn’t an option, an official said.

The sudden move seemed to catch some in the White House off guard. Officials learned of the cancellation – and initial description of an “emergency” – at the same time as the public, learning only later that there was no emergency and that Pence never left the ground.

It immediately set off speculation in Washington that the reason he returned was related to health or national security, something his office later denied.

“This is not health related for the VP or President. Nothing related to national security,” a senior administration official said, noting around noon that Pence was at the White House.

Though officials sought to downplay the matter in the aftermath, several Republican lawmakers close to the administration said they were skeptical that the vice president would suddenly return if it weren’t urgent.

Trump, who was not seen in public at all on Tuesday, seemed to dispel the sense of crisis when he tweeted in the middle of the speculation a link to logistical details of his July Fourth “Salute to America” event.

As they tried to contain the panic, people close to the vice president initially said it was a personal matter, though an official said later that it wasn’t. But it set off a furor in the West Wing, because aides there also were not informed what caused the cancellation yet were faced with questions from reporters.

Aides later conceded the matter had been handled poorly, but still refused to offer a reason for the scramble.

Marc Short, the vice president’s chief of staff, intensified speculation when he told reporters they would find out the cause “in a few weeks.”

The vice president’s press secretary wrote on Twitter that the event in New Hampshire would be rescheduled “very soon.” But it won’t be Wednesday – Pence’s schedule listed no public events.