Both sides, standing at different ends of the airfield, ready to fight, when...
"ANTHONY EDWARD STARK AND STEVEN GRANT ROGERS!"
Both teams jumped, even the master assassins, at the sound of the fuming Pepper Potts' voice. The angry strawberry blonde strode to the middle of the battlefield, the two men walking towards as well.
"You" Pepper turned to Tony
"Shut up. I'm gone for three days and you are already in a fight?! FRIDAY calls me, telling me about avenging your parents and whatnot and how the team is split up into two. A civil war, really?" Tony opens his mouth to protest but closed it seeing the glare his girlfriend was giving him.
"And you" She turns to the Captain "I know this wasn't just Tony's fault. James knows what he's done and he will get punished for it, luckily, I struck a deal with the government giving you six months to prove he is mentally stable and I will be deciding his consequence. But really, you reckless son of a bitches could not even attempt to talk about this?"
She then looks at both sides "And the rest of you, choosing sides just made this worse. You're all supposed to be more evolved. How do you help by getting three other non Avengers involved, one of which is a minor?! This ends NOW! Do I make myself clear?"
A mumble of "Yes Pepper" came and Pepper nodded before hooking the Iron Man and Captain America's ears and dragging them to the quinjet, along with the rest of the Avengers, who had their heads bowed down in shame and fear and put their weapons away in designated boxes. Peter gave Pepper Steve's shield, no one having the balls to ask what she would do with it.
"I'm still telling your aunt about this Peter Parker"
And that ladies and gentlemen is how Virginia 'Pepper' Potts stopped Civil War like the BAMF she is.