Don't use the table names in the select list:
CREATE VIEW IMEXtrlrUtilUNIONasapSM_VW as
SELECT top 100 percent OrderNbr, City, Shipper, Weight
from IMEXtrlrUtilShipMat_VW
Union
select top 100 percent OrderNbr, City, Shipper, Weight
from IMEXtrlrUtilASAP_VW
ORDER BY OrderNbr, City, Shipper
For the record, even if not including and Order By clause, I advocate never using Select * in a view. If you change the underlying schema of a table, you will have to recompile any views using Select * before they work correctly.