In the autumn of 1943 Cantacuzino became ill and was interned in a hospital and was kept from the front so he could rest and recuperate. On 10 February 1944 he returned to active duty in the 7th Fighter Group, which was sent to the front with the Soviets in Moldova. On 15 April, there was a USAAF raid and Cantacuzino and his wingmen attacked the bomber formations and shot down six B-24 Liberators (the prince got one himself). He continued flying missions against the Soviet Air Force and scored several victories.