Megellas was originally assigned to the Signal Corps, but grew tired of the required additional schooling and volunteered to become a paratrooper in order to see combat. He was assigned to H Company, 3rd Battalion, 504th Paracute Infantry Regiment, 82nd Airborne Division. He first experienced combat in the mountains outside Naples, Italy, near Venafro, where he was wounded and hospitalized. In October 1943, while the remainder of the 82nd Airborne departed Italy to recoup before the invasion of Normandy, the 504th PIR remained behind and took part in Operation Shingle. On January 22, 1944, the 504th took part in an amphibious assault at Anzio. The fighting took a heavy toll, Megellas being wounded again. It was not until April before the regiment was withdrawn. Due to the losses at Anzio, the 504th did not participate in the D-Day Normandy Landings. They did, however, parachute into the Netherlands as part of Operation Market Garden, the airborne invasion of that country.