Fender gave some insight to the inspiration and context of the track when it was released on March 5, 2019:

This song started out when I saw the term ‘Hypersonic Missiles’ in a newspaper. It’s a newly developed Russian missile that travels at something like nine times the speed of sound, which is essentially unstoppable. America currently has no defence against such a weapon, they would be helpless in the wake of an attack, as you have roughly six minutes from the time it is launched to the time it strikes.

In many ways, ‘Hypersonic Missiles’ is an unorthodox love song. It’s [sic] main focus is on the world around the narrator, who is a complete tin foil hatter. They are convinced the world is on its last legs; they know that it is rife with injustice but feel completely helpless and lacking the necessary intelligence to change it while remaining hopelessly addicted to the fruits of consumerism.

Amongst all the chaos is love and celebration, there is this glimmer of hope that runs through the song, a little notion that no matter what happens, these two people are gonna have a fucking good time regardless of the tyrants that run their world, and regardless of the imminent doom from these ‘Hypersonic Missiles’. "

The atmospheric saxophone heard throughout the outro was recorded by the 1975 saxophonist John Waugh. Both John and Sam confirmed this on their respected social media accounts.