[Misiur]

pawn Code:

stock IsValidModelPlane(modelid) 
{ 
    #define    MAX_BAD_MODELS 128 
    new allowedmodels[MAX_BAD_MODELS] = 
    { 
        511, 512, 513, 593, 417, 469, 487, 548, 563 
    }; 
    if (modelid < 400 || modelid > 611) return false; 
    for (new i = 0; i < MAX_BAD_MODELS; i++) 
    { 
        if (modelid == allowedmodels[i]) return true; 
    } 
    #undef MAX_BAD_MODELS 

    return false; 
}

By your logic it must match all allowedmodels, by the code I gave you only single one is required.