$1,500 [BETA] per teammate you kill. That includes passengers who die when you crash a helicopter, and you can be fined when a passenger jumps out and breaks their legs even if your landing was fine.
The Season 1 changelog lists no change to it. Friendly markers render in your faction's colour, so on Valkyra your teammates are red: check before you fire. Learn to fly in the free firing range, never with passengers, and stock spare parachutes in the aircraft before takeoff.