Current and former employees of Boeing made damning allegations about the safety of the company's planes during a Senate hearing on Wednesday.

The whistleblowers said Boeing is engaged in a "criminal" coverup of critical defects following the Alaska Airlines blowout in January, which led to a Justice Department probe and a shakeup at the top of the corporation.

President Biden's airplane, Air Force One, is a Boeing 747.

A faulty door plug blew out on an Alaska Airlines flight in January, causing a gaping hole in the fuselage of the Boeing 737 MAX 9 plane.

"Coverup" at Boeing

Boeing says it doesn't have documentation about who worked on the faulty door plug, but former Boeing manager Ed Pierson said that's a lie. He said a "coverup" is ongoing at the company.

"I'm not going to sugarcoat this. This is a criminal cover-up," Pierson said. "Records do, in fact, exist. I know this because I personally passed them to the FBI."

A Boeing engineer, Sam Salehpour, said he has faced retaliation for voicing his concerns with the structural integrity of the 787 and 777 models.

"I literally saw people jumping on the pieces of the airplane to get them to align," he said. "I call it the Tarzan effect."

Boeing said "retaliation is strictly prohibited at Boeing" and defended the safety of its planes.

"We know we have more work to do and we are taking action across our company," the company said.

FAA under audit, Buttigieg responds

While Boeing comes under scrutiny, some have faulted the federal government as well for a hand-in-glove relationship with the manufacturer.

Pierson said nothing has changed at Boeing since two 737 Max crashes killed hundreds of people in 2018 and 2019, and the government is partly to blame.

"The world is shocked to learn about Boeing's current production quality issues. I'm not surprised because nothing changed after the two crashes," Pierson said.

"Government authorities ignored Boeing's manufacturing problems until the Alaska accident. Passengers shouldn't have to rely on whistleblowers to provide the truth."

The internal watchdog at the Transportation Department has opened a probe into the Federal Aviation Administration (FAA) and its oversight of Boeing, Reuters reported.

Transportation secretary Pete Buttigieg called the new probe a "healthy" development.

"Obviously, when something is in the news, they're going to take a closer look the same way we're taking a closer look at Boeing," he said.