[Fedee!]

Try this:

pawn Код:

//At Top
#define dcmd(%1,%2,%3) if ((strcmp((%3)[1], #%1, true, (%2)) == 0) && ((((%3)[(%2) + 1] == 0) && (dcmd_%1(playerid, "")))||(((%3)[(%2) + 1] == 32) && (dcmd_%1(playerid, (%3)[(%2) + 2]))))) return 1
forward Car();

//The Command
dcmd_p(playerid,params[])
{
    if(strlen(params) == 0) return SendClientMessage(playerid, red, "Usage: /p (Text)");
    for (new i = 0; i < GetMaxPlayers(); i++)
    {
        if(!IsPlayerConnected(i) || !IsPlayerInAnyVehicle(i))
        {
            Car();
        }
        return 1;
    }
    return 1;
}

public OnPlayerCommandText(playerid, cmdtext[])
{
    dcmd(p,1,cmdtext);
    return 1;
}

public Car()
{
    new vehicleid;
    vehicleid = GetPlayerVehicleID(i);
    switch(GetVehicleModel(vehicleid))
    {
        case 417 ,425, 447, 592, 577, 511, 512,
        593, 520, 553, 476, 519, 460, 513, 548,
        487, 488, 497, 563, 469:
        {
            new string[128];
            new pName[MAX_PLAYER_NAME];
            GetPlayerName(playerid, pName, sizeof(pName));
            format(string,sizeof(string),"Pilot Chat: %s: %s",pName, params);
            SendClientMessage(i, green, string);
        }
        default: return SendClientMessage(playerid,COLOR_RED,"[ERROR]: You must be in a valid vehicle!.");
    }
    return 1;
}