Military personnel accidentally triggered an inflatable slide attached to President Donald Trump’s Qatari-donated Air Force One plane Wednesday, a person briefed on the matter told NBC News.

The slide inflated just before Trump was set to board the plane and head to Dallas for the GOP midterm convention. Instead of immediately exiting Marine One to board the plane as he usually does, Trump remained on the helicopter for several minutes.

He eventually walked out on the tarmac while officials looked at the slide, telling reporters that they were just “checking the slide.”

“As the President has said, the slide was checked out to make sure everything works perfectly,” White House communications director Steven Cheung said later in a statement. “Air Force One is on its way to Dallas so he can deliver his much-anticipated speech to a raucous and sold-out crowd.”

Trump told reporters before he boarded that there were no security concerns.

“No, they were checking it before, and they just wanted to make sure. So they’ve — I guess they’ve already put it up. They want to make sure everything works perfectly,” he said.

Asked again whether he believed the plane was safe to fly, Trump chuckled and said, “Yeah, I am or I wouldn’t be on it.”

The plane landed safely in Dallas around 5:15 p.m. ET, a couple of hours later than had been expected.

Concerns have swirled around the Qatari-donated jet’s security capabilities for months, particularly after the Secret Service recommended that Trump instead fly on a plane that had previously been used as Air Force One.

While White House officials have repeated publicly that the new plane does not have security issues, two sources familiar with the matter acknowledged in July that it does not have all the security measures that are on the older aircraft previously used by Trump.

Trump said later in July that the new jet would be sent away to get upgrades to get “maxed out,” though then-press secretary Karoline Leavitt said at the time that it was just getting “upgrades and enhancements” and was “perfectly safe” for Trump to use.

The Qatari royal family donated the superluxury Boeing 747-8 jumbo jet last year for Trump to use while Boeing works to provide long-delayed updated Air Force One planes that are expected in 2028.