Trivia: Stan Lee makes his usual cameo as the guy that accidentally gets his car shrunk by Hope during the climactic chase. Sadly, this was the last Stan Lee cameo released before his death in November, 2018. (Although he had already filmed cameos for several other upcoming films before his death).
Continuity mistake: Scott grabs the Greatest Grandma trophy from its stem. Shot changes and he is grabbing the rear side. This swaps back and forth.
Continuity mistake: Before Hope grabs the backpack, there's a small soccer ball next to it by the edge of the rack. When she grabs it, the ball doesn't drop. It simply vanishes, as proven after Scott opens the backpack.
Continuity mistake: Scott's size changes when he is in front of the backpack rack. On the first shot his head is 10 centimetres below a shelf, but a shot later he's 30 centimetres below, despite him looking upwards; so he's in fact way smaller.
Continuity mistake: When the shrunken car is surrounded by pigeons, it's an all-glass roof, or black. When the shrunken car drives through a pipe later, its roof is silver. It changes back and forth again, just before/after Hank shrinks it.
Continuity mistake: At the start when Hope is playing in her room, in a wide shot there's a wooden stand with a plant on it by the teddy bear in the background. In a closeup of her this stand has vanished.
Answer: They provided Ant-Man with superhero tech without signing on to the Accords. So when Scott participated in the airport battle, Hank and Hope became guilty by association.
Phaneron ★