Gerd von Rundstedt and Walter Model both presented plans for the Ardennes Offensive: Rundstedt's Fall Martin envisoned three armies advancing in a pincer movement, two panzer armies out of the Ardennes, and the Fifteenth Army from Roermond, meeting near Liege to sweep the U.S. First Army and elements of the Ninth Army into a pocket around Aachen. Model's plan, Herbstnebel ("Autumn Mist") envisioned a similar thrust through the Ardennes, but with the Seventh Army used behind the main advance as it turned north to widen the penetration, rolling up the Allied line towards Aachen. Model agreed to support Rundstedt's plan in the hope of bringing Hitler around to supporting the "small solution" or "Little Slam" as opposed to the ludicrous "Grand Slam" he envisioned lunging towards Antwerp. In the event, Hitler could not be moved, though as a sop to Model, the offensive plan was renamed from Wacht am Rhein to Herbstnebel.

Sources:

Antony Beevor, Ardennes 1944: Hitler's Last Gamble

Peter Caddick-Adams, Snow and Steel: The Battle of the Bulge 1944-45