Soldier Boy is seen pouring Coca Cola into a glass of milk and drinking the mixture. This is a hangover cure from 1938.
Homelander tells Black Noir that unlike others, he can clearly see his face due to his ability of X-ray vision. This is a subtle dig at a plot loophole in the comics. While Black Noir's identity is a crucial part of the comics' plot, Homelander never once attempts to see past Black Noir's cloth mask.
The irresistible urge to pull your hair out is a mental disorder called Trichotillomania.
The names of the runners in the track meet that Nathan is watching on TV are the names of the crew members from the post-production and VFX departments.
Robert 'Bobby' Singer, played by Jim Beaver, is shown with his entourage visiting Sioux Falls, South Dakota, hometown of Jim Beaver's character in 'Supernatural,' who was also named Bobby Singer.