I have learned first hand that the only way to unlock the classic 'Wings & Scales' Costume in Captain America: Super Soldier is to earn 25,000 intel points(exp). Something I accomplished 2 hours after finishing my initial playthrough. There's no way to begin a new game with the Classic Cap outfit. So on my second playthrough, I've stopped at the beginning of the third chapter of the campaign and have begun grinding out 25,000 intel points on combat challenges. I started yesterday, and so far I'm at approximately 6,000.