Through which companies have products been shipped the most times to the city of Aachen?
shipped the most times refer to MAX(COUNT(ShipVia)); city of Aachen refers to ShipCity = 'Aache'; companies refers to CompanyName;
SELECT T2.CompanyName FROM Orders AS T1 INNER JOIN Shippers AS T2 ON T1.ShipVia = T2.ShipperID WHERE T1.ShipCity = 'Aachen' GROUP BY T2.CompanyName ORDER BY COUNT(T1.ShipVia) DESC LIMIT 1