LONDON—The global semiconductor chip shortage cost Volkswagen and Stellantis a combined 1.4 million vehicles in lost production in the third quarter, Europe’s two biggest carmakers said on Thursday, though both reported some early signs of improvement. Volkswagen AG, Europe’s top car company and also the world’s No. 2, cut its outlook for deliveries, toned down sales expectations, and warned of cost cuts as it reported lower-than-expected quarterly operating profit. The German company said it had made around 800,000 fewer cars, or about 35 percent less than in the same quarter in 2020. Stellantis, the world’s fourth largest automaker, posted a 14 percent fall in pro-forma quarterly revenue after chip shortages cut planned quarterly production by 30 percent, or 600,000 vehicles. Stellantis finance chief Richard Palmer reported a “moderate” improvement in chip supply in October, and expected that to continue through the fourth quarter. But he added supply chain problems meant …