Answer: Flight stabilization
Tony speaks to Rhodes specifically, wanting him in for what he has planned, but Rhodes suggests that his friend needs time. Instead, Stark takes to his private server, J.A.R.V.I.S., and plans something out on his own, building while the terrorists attempt to recover the buried pieces of his destroyed suit in the desert. Obadiah, returning from a board meeting, tells Tony that the directors of the company are planning an injunction, claiming Tony's post-traumatic stress as the reason for the destruction of the company. It doesn't matter too much though. With more time, Tony constructs a sleeker suit, making it capable of controlled flight and taking it for a spin in the skies above his Malibu mansion. He performs an altitude test, nearly dying due to an ice build-up, but it ends up being a success. That night, he opens a package left behind by Pepper. She took his first ARC device and boxed it up as a gift, labeling it as 'proof Tony Stark has a heart'. After this, he drafts up his Mark III and heads out to crash a party.