[Golimad]

You'll have to use some of your knowledge .. the main idea is to make a variable
new bool:PlayerCanShootMissile[MAX_PLAYERS]; // you put this in top of script
PlayerCanShootMissile[playerid] = true; // On player connect

You'll use this public funtion : OnPlayerKeyStateChange ( In case player pressed FIRE_KEY && Player is in a hunter or tank or hydra && PlayerCanShootMissile[playerid] == true) you do : PlayerCanShootMissile[playerid] = false; SetTimerEx("ResetMissileVariable" ..... );
Else ( you eject player from vehicle + you send him a client message ( Do not abuse .. )


forward ResetMissileVariable(playerid);
public ResetMissileVariable(playerid)
{
PlayerCanShootMissile[playerid] = true;
}

I hope you see my points ... I hope this helped you

// To eject player from vehicle use this : RemovePlayerFromVehicle(playerid);