Freedom Files is the last mission in Grand Theft Auto Advance, unlocked after protagpnist Mike spares King Courtney's life in the previous mission, Assault Joint.
Mission
Mike realizes the cops have him surrounded and wishes to have a tank to get through them and reach the airport, where Cisco, the deceased leader of the Colombian Cartel, has left a plane for him to leave Liberty City. When the cutscene ends, a tank appears and Mike gets on it. With a 6-star wanted level, you have to get to Francis International Airport in time. If the tank is destroyed or the player dies/gets arrested, the mission is failed. Although, the tank can't be easily damaged by the cops. The game will give you instructions how to fire the cannons of the tank and destroy the cop cars which block the road. Once you reach the airport, enter the marker and a cutscene starts.
Mike leaves Liberty City, and remembers his friends, the bar-tender Jonnie, and Cisco, both killed, and 8-Ball, who was arrested. Then a plane is shown leaving Liberty City (for Colombia, as Mike says).
Reward
The reward for this mission is $40000 and completing the main story.
Trivia
The airport is inaccesible in the game, so it's not viewed in this mission, although in the final cutscene it's briefly seen, when the plane takes off.
The plain that leaves Liberty City with Mike inside looks like a Shamal.