EnableFlyCmdMangosZero02.cpp

//src\game\object\Player.cpp
void Player::SetCanFly(bool enable)
{
    WorldPacket data;
    if (enable)
        data.Initialize(MSG_MOVE_START_SWIM, 12);
    else
        data.Initialize(MSG_MOVE_STOP_SWIM, 12);

    data << GetPackGUID();
    data << uint32(0);
    SendMessageToSet(&data, true);

    /*data.Initialize(MSG_MOVE_UPDATE_CAN_FLY, 64); //hope we can skip this
    data << GetPackGUID();
    m_movementInfo.Write(data);
    SendMessageToSet(&data, false);*/
}


//src\game\chatCommands\Level3.cpp It's already present in MangosZero
#include "Opcodes.h"
bool ChatHandler::HandleGMFlyCommand(char* args)
{
    bool value;
    if (!ExtractOnOff(&args, value))
    {
        SendSysMessage(LANG_USE_BOL);
        SetSentErrorMessage(true);
        return false;
    }

    Player* target = getSelectedPlayer();
    if (!target)
    {
        target = m_session->GetPlayer();
    }

    /* [-ZERO] Need reimplement in another way //hope we can skip this
    {
        SendSysMessage(LANG_USE_BOL);
        return false;
    }*/
    target->SetCanFly(value);
    PSendSysMessage(LANG_COMMAND_FLYMODE_STATUS, GetNameLink(target).c_str(), args); //not sure LANG_COMMAND_FLYMODE_STATUS exists in MangosZero, might need fix here
    return true;
}