AIR Force One is probably the most famous plane in the skies but it has four shadowy 'brothers' whose roles are far more important.

The super-secret E-4B 'Doomsday' 747 jets follow US President Donald Trump on his travels around the globe just in case a sudden nuclear war breaks out.

11 There are four E-4B 'Nightwatch' planes in a fleet that are made up of specially modified Boeing 747s

11 The super-secret jets follow US President Trump on his travels around the globe Credit: Getty Images

11 The planes' equipment is deliberately dated to prevent any hacking Credit: horizontal rain/youtube

11 One of the jet's military command centres where the President can call the shots Credit: horizontal rain/youtube

The planes, called 'National Airborne Operation Centres', have the ability to communicate with anyone from anywhere in the world.

It's sole role is to support military analysts and strategists during a military crisis.

The design of the plane is meant to survive an electromagnetic pulse with all the systems left intact.

Triple-decker Doomsday planes even use traditional analogue flight instruments because they are less vulnerable to a cyber attack.

11 Pilot Lt. Col Dan McDonald flies a E-4B NOAC as a KC-135R tanker refuels his plane during a flight back to Andrews Air Force Base in Maryland Credit: Reuters

11 The triple-decker planes can sleep crews of up to 112 Credit: horizontal rain/youtube

11 The aeroplanes, while not technically secret, are rarely mentioned Credit: horizontal rain/youtube

11 The jets act as flying shadows to Air Force One Credit: Getty Images - WireImage

There are four E-4B 'Nightwatch' planes in the fleet that are made up of specially modified Boeing 747s.

They follow the Commander in Chief whenever he takes to the skies in Air Force One.

The planes are outfitted as complete command centres for the President and his top officials including the Secretary of Defence and the Joint Chiefs of Staff in the case of nuclear war or national emergency.

The aeroplanes, while not technically secret, are rarely mentioned - the Air Force does not even publicly acknowledge owning some of them.

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In operation since the 1970s, these airborne command posts were long considered the best chance for a Cold War president to survive a nuclear attack.

Unlike the ceremonial and comfort-focused Air Force One, the E-4B airborne command posts are flying war-rooms—staffed by dozens of military analysts, strategists and communication aides who would guide the President through the first days of a nuclear war.

The planes also include special gear like a five-mile-long trailing wire antenna that would ensure that the president could remain in contact with the nuclear submarine fleet even after ground-based communications had been destroyed.

11 US Secretary of Defence Donald Rumsfeld aboard the Air Force E-4B airborne command and control aircraft in 2004 Credit: Reuters

11 One of the flying war-rooms - staffed by dozens of military analysts Credit: horizontal rain/youtube

11 The Doomsday planes are known to their crews as “Air Force One When It Counts” Credit: horizontal rain/youtube

Through the final decades of the Cold War, an E-4B Nightwatch plane always stood on alert at Andrews Air Force Base, ready to whisk the president skyward with just 15 minutes’ warning. E

Even today, one of those four Doomsday planes, known to their crews as “Air Force One When It Counts,” regularly travels with or near the Presidentat all times.

When the president is in the United States, an E-4B always remains on alert at Offutt Air Force Base in Omaha, Nebraska, its engines turning 24 hours a day, ready to launch and rendezvous with the president in the event of an emergency evacuation.

Yet even those Doomsday planes represent just one corner of the emergency air fleet at the president’s fingertips, all of which is easy to hide inside the large-scale logistics of a Presidential trip.