Though the above cover suggests some kind of ground to spaceship battle with "ray"
weapons of the future, the setting is drawn as an air to ground battle. The ground
"gunners" could just as readily be operating a World War II "machine gun" as a
futuristic laser cannon. Likewise, the spacecraft could be a propeller driven
dive bomber of the same era strafing the Earth with its bullets.
Comparing the use of two technologies in the same battle setting is an interesting
science study. A difficulty of the WWII machine gun was aiming the weapon
properly. Gunners found hitting their targets quite difficult at aircraft speeds of
hundreds of miles per hour. Spacecraft travel at miles per second. What laser-gunner
could hit a target at such a speed at the shown range?