Mr Spaceship - Philip K. Dick

Mr Spaceship (short story) by Philip K. Dick
Humanity is at war with the “Yuks” -- an alien species that do not use mechanical spaceships. Instead, they build with life forms.
In a desperate attempt to end the war and save the planet, a team of researchers led by Philip Kramer build a spaceship powered by a human brain.
Published 1953 ~ Imagination Stories of Science and Fantasy