I am not able to recreate this behavior in Dreamweaver.
When I save a recordset that uses the concat function in the group by clause, the concat function is not removed.
Try editing the code directly.
change line 83:
$query_RsAM = "SELECT SUM(Air) AS numCount FROM tripmanifest GROUP BY Month, Day, Year, ampm";
to:
$query_RsAM = "SELECT SUM(Air) AS numCount FROM tripmanifest GROUP BY CONCAT(Month, Day, Year, ampm)";