The story is famous, at least as far as famous Marvel Cinematic Universe stories go. Marvel President Kevin Feige gave a note to Christopher Markus and Stephen McFeely as they duo toiled away on the second Captain America movie, Captain America: The Winter Soldier. "I want to see Helicarriers falling from the sky," was his note, paraphrased here for the benefit of the story. And so, Markus and McFeely set about coming up with a host of reasons why The Winter Solider needed to end with a third-act conclusion involving massive S.H.I.E.L.D. Helicarriers. Because, for reasons that make sense, what Feige wants, Feige gets.
As it turns out, there was something that Kevin Feige really wanted to see in Captain America: Civil War, and it fell in the laps of Christopher Markus and Stephen McFeely to make it happen, as well. They shared this anecdote from the stage of the Horton Grand Theater in downtown San Diego during Comic-Con, where they were explaining their fight to be able to use Giant Man as a character in the movie's airport battle sequence. Markus explained:
Such a fun scene. If you don't recall, this is the culmination of Ant-Man (Paul Rudd) riding on one of Hawkeye's (Jeremy Renner) arrowheads. The tip explodes, sending Scott Lang through the sky, and when he comes down, he's sliding across the surface of Tony Stark's armor. Once inside, the inch-sized hero starts mucking with the inner workings of Tony's suit, sending the billionaire playboy into a bit of a fit until his built in defense systems kick in... sending Ant-Man running.
Fans know it actually references a famous comic cover:
So now that we know this little tidbit was Kevin Feige's doing, it cements the opinion that the man simply understands what works and what doesn't about his Marvel characters, and the perks of their abilities. Earlier in the same panel, Markus and McFeely were talking about how every fight in Civil War served multiple purposes, and if it's just super-powered beings hammering away at each other, then it's boring and disinteresting. But knowing that the most damage Ant-Man could do to another Avengers would be to get inside Iron Man and mess with his armor from within is a clever and fun way to pit these two heroes against each other.
We can only hope we get a rematch once Steve Rogers (Chris Evans) breaks Lang out of prison.