The company behind the U.S. Air Force's new so-called "Doomsday" planes revealed details Wednesday of how it was developing the aircraft designed to withstand a nuclear blast.

The aircraft - which can seat up to 111 people - are capable of withstanding nuclear blasts and electromagnetic pulses, according to officials.

Rolls Royce secured a contract for a nuclear-proof Doomsday plane, contributing cutting-edge technology to the US Air Force's SAOC project.

A contract to upgrade America’s “doomsday planes” has been handed to Rolls-Royce. The United States has a fleet of four customised Boeing 747 or Boeing-E4 jets, formally known as the Survivable Airborne Operations Center.

The 'doomsday' plane, which can survive a nuclear blast, would transport the US President and top military leaders in the event of a national emergency.

Rolls-Royce's involvement comes after the Pentagon awarded a $13 billion contract to develop the new generation of the planes to defence giant Sierra Nevada Corporation. Rolls is thought to have been brought on to help work on the plane’s propulsion systems.

Rolls-Royce has been chosen to supply technology for a new version of the American military aircraft nicknamed the “Doomsday plane” for its ability to survive a nuclear blast.

Sierra Nevada Corp. was awarded a multibillion-dollar Air Force contract prior to its purchase of the Korean Air jets.