A 2021 report made public through the Freedom of Information Act outlines the unclassified requirements for the replacement 747s under construction. At the top of the list — survivability and communications.
The government decided more than a decade ago that the new planes had to have four engines so they could remain airborne if one or two fail, said Deborah Lee James, who was Air Force secretary at the time. That creates a challenge because 747s are no longer manufactured, which could make spare parts harder to come by.
Air Force One also has to have the highest level of classified communications, anti-jamming capabilities and external protections against foreign surveillance, so the president can securely command military forces and nuclear weapons during a national emergency. It's an extremely sensitive and complex system, including video, voice and data transmissions.