Experts working with Homeland Security hacked into Boeing 757

There's some unsettling news about one of America's most widely-used jetliners.

In a test, experts working with Homeland Security hacked into a Boeing 757. The team of researchers needed only two days in September 2016 to remotely hack into a 757 parked at the airport in Atlantic City, New Jersey.

Speaking at a conference this week, Robert Hickey of the Department of Homeland Security said his team used "typical stuff that could get through security" and hacked into the aircraft systems using "radio frequency communications."

"The 757 hasn't been in production since 2004, but the aging workhorse is still flown by major airlines like United, Delta and American," said Mark Rosenker, the former chair of the National Transportation Safety Board.

President Trump's personal jet is a 757. So is the plane Vice President Pence often uses -- including on his recent trip to Texas.

The classified DHS testing followed a 2015 incident where a passenger told the FBI he had gained control of a plane's engine by hacking into the airline's in-flight entertainment system.

That same year, the Government Accountability Office warned about "potential malicious actors" accessing an airliner's Wi-Fi network.

Homeland Security says the recent testing was in an "artificial environment and risk reduction measures were already in place."

Boeing observed the testing and was briefed on its results. In a statement, the company says, "We firmly believe that the test did not identify any cyber vulnerabilities in the 757, or any other boeing aircraft."

An official briefed on the testing does not believe it revealed an "extreme vulnerability" to airliners, since it required a very specific approach in a very specific way on an older aircraft with an older system. The official adds, it was good information to have, "but I'm not afraid to fly."