The headquarters of SHIELD as seen in Captain America: The Winter Soldier is seen being constructed in the film's flashback opening scene.
John Slattery returns as Tony Stark's father, reprising his role from Iron Man 2!
Joining him is Hayley Atwell as an older Peggy Carter as well, in-between the events of Captain America: The First Avenger and The Winter Soldier.
In the film Scott stays at The Milgrom Hotel, named for Marvel writer/artist Al Milgrom.
Though The Mandarin may have been defeated in Iron Man 3, the Ten Rings is still around apparently. Barely visible, but still very much there, the man standing behind Cory Stoll has a Ten Rings tattoo on his neck, signifying his membership in the group.
In the pages of Marvel Comics, Darren Cross did have a rival company to the likes of Hank Pym and Tony Stark, with this model serving as a reference to what he hopes to create in the film.
While trying to downplay the truth of Hank Pym's life as Ant-Man, Cross refers to the stories as "Tales to Astonish," the name of the comic book where Ant-Man made his debut back in 1962.
The soda from The Incredible Hulk appears briefly in the film as a street advertisement.
Kirby is a real brand of vacuums, but this also works as a reference to Hank Pym's co-creator, comic book legend Jack Kirby.
Comedian Garrett Morris cameos as the Taxi driver. His cameo comes from having played Ant-Man in a skit on Saturday Night Live.
The events of Age of Ultron are referenced in the newspaper seen in the film.
You probably shouldn't notice this when you're actually watching the movie, but the article next to the one about Scott has something to say about Cryptozoologists and Sasquatch. This is a double Easter egg since the production codename for Ant-Man was Bigfoot.
The Stark warehouses that Hank wants to rob are actually the new Avengers base as seen in Avengers: Age of Ultron.
Luis whistles the theme song to Disney's It's a Small World while trying to blend in.
The microscopic animals appear as Scott begins to shrink down.
We know that Janet was lost in the quantum realm and she can briefly be seen in the film for just a few frames.
Lee appears as a bartender in the final minutes of the film.
This is a reference to the upcoming addition of Spider-Man to the Marvel Cinematic Universe.
The Wasp is coming and Hope will wear the wings.