A little-known company based in Boulder, Colorado, is pursuing an ambitious, borderline outlandish goal: creating the world’s largest airplane. When completed, the incredibly long 108-meter plane (roughly the length of an NFL football field) is expected to have a wingspan of over 260 feet and could offer 12 times the cargo space of Boeing C-17 Globemaster III.

While your average passenger jet can usually hold plenty of people, one in particular can carry almost 1,000, and it's flying the skies right now.

Two decks down the length of the plane, and carrying over 650 passengers, this 1990s proposed version of the Boeing 747x would not only be the biggest passenger aircraft flying in the sky, but it would put crush the efforts by Airbus to build their own double-decker forever.

The mighty C-5 Galaxy—the largest strategic airlifter in the U.S. Air Force—is an engineering spectacle. It can kneel down, rotate its landing gear 90 degrees, and even travel in reverse! But what truly boggles the mind is its secret nickname,