Mission 14: Journey Home. It begins with Edge commanding and leading you on a fly by where the Vice President addresses the nation. Then the Yukes attack, you're trying to cover the evacuation against at this point the toughest enemies in the game, then Chopper gets hit and holds out as long as he can until everyone escapes, but the ejector is stuck.
That's not the best part though. His death clearly leaves Wardog shattered, and they fight back, the enemy believes demons had literally taken them over and That One Level suddenly becomes a Curb-Stomp Battle.
Mission 26: Aces: the Tunnel Run, with the second most driving music in the game, surpassed only by the The Unsung War itself, flying at Mach 2 down the tunnel, and then Bartlet comes from the other direction.
Bartlet: I'm going to pass by you on the count of 3.