In September 1944 the Allies launched Operation Market Garden, an unsuccessful, airborne operation, fought in the Netherlands and Germany. The goal of the operation was to encircle the Ruhr valley, the center of German industry, with a pincer movement.
Including the Battle for Arnhem, Operation Market Garden, was the largest airborne battle in history. Allied forces were commanded by Field Marshal Bernard Montgomery . German forces were under the command of Generalfeldmarschall Walter Model .
With thousands of aircraft and armored vehicles, and hundreds of thousands of troops, Operation Market Garden was the only major Allied defeat of the Northwest European campaign.
Perhaps due to the failure of Operation Market Garden, the Germans were able to take advantage of tactical errors and counterattack in December 1944 with the infamous Battle of the Bulge.
Excellent overview of Operation Market Garden