Howard Stark mentions that he spent a weekend with Hedy Lamarr, a movie star who was belatedly recognized as an under-appreciated genius inventor who helped develop frequency-hopping spread spectrum communication, a technology that served as a key forerunner to Bluetooth and Wi-Fi technology.
The ancient illustration of the tesseract spells out "SPACESTONE" in old Norse futhark script.
Carter's superhero costume, especially the shirt, includes elements of the costume of Marvel's period British World War II superhero, Union Jack, with the Union Flag making up the chest symbol.
Captain Carter's theme song was based on inverting the Captain America theme (When Captain America's theme goes up, Captain Carter's goes down, and vice versa)
One spinoff idea for the episode would've had Steve falling off the HYDRA train instead of Bucky, and end up becoming the MCU's equivalent of Captain Hydra, a high-ranking commander for HYDRA. This would've forced Peggy, Howard, Bucky and Red Skull to work together to defeat Steve. The idea was scrapped due to the story being too similar to the original episode's concept, though it did get A.C Bradley hired as the showrunner.