From what you explained it doesn't look like you need SUM or any aggregate functions.
Try something like-
SELECT T1.Sno, T1.Overallqty, T1.Address, T2.Sno, T2.shiqty, T2.Airqty, T2.Address
FROM Table1 T1
INNER JOIN Table2 T2 ON T1.Sno=T2.Sno
WHERE T1.Overallqty - (T2.shiqty + T2.Airqty)>0
Hope, it helps.
Please let me know if your requirement is somethingelse than this. :)