From Orly or Charles de Gaulle to Chartres

By public transport, first to Paris-Montparnasse: from Orly, metro line 14 and change to the metro to Montparnasse; from Charles de Gaulle, RER B to Saint-Michel and metro 4. There, a train to Chartres. Note: the Île-de-France airport ticket only covers as far as Montparnasse, and the train to Chartres, which leaves the region, is paid for separately with SNCF. By car, Orly is 75 km away, about 45 minutes, and Charles de Gaulle 120 km, an hour and twenty.