1938, No. 233 and 224 Squadrons were replaced by Bomber Command 106 and 185 Squadrons equipped initially with Fairey Battles before re-equipping with Handley Page Hampdens. Ansons of 269 Squadron and Vickers Vildebeests of 42 (Torpedo Bomber) Squadron relocated here during the Munich crisis while 106 and 185 moved temporarily to RAF Cottesmore before moving back to Thornaby after the crisis. Thornaby was one of only ten airfields in the country known to have had paved runways before the war started, although runways were under construction at eight fighter stations due to an Air Ministry conference on 28 April 1939, but only two of these were completed by 3 September 1939. Second World War On 20 March 1939 No. 608 Squadron were transferred to No. 18 Group Coastal Command and with war looming were embodied into the RAF for full-time duties on 24 August 1939. Numbers 106 and 185 Bomber Command Squadrons moved to Cottesmore in August 1939 and Coastal Command 220 Squadron arrived with Ansons on 21 August from RAF Bircham Newton, thereafter the station remained within Coastal Command until the end of hostilities. Almost immediately after arriving No. 220 began to re-equip with the American built Lockheed Hudson, during this period the instructors of the 220 Squadron Hudson Conversion Flight (The Hudson Circus) along with 220 and 608 Squadrons were inspected by King George VI who visited the station on 1 November 1939 accompanied by Chief Of Air Staff together with Sir Frederick Bowhill and Air Commodore Breeze, AOC 18 Group. A detachment from 224 Squadron (the first squadron to become operational on the Hudson) arrived from Leuchars to cover 220 Squadron's "war work", whilst they were being converted onto the Hudson. On 16 October 1939 the first 220 Squadron Hudson operation took place, during the conversion the squadron carried on for a short time with the Anson due to a shortage of serviceable Hudsons, a number of which were awaiting modifications such as installation of gun turrets, bomb racks and fitting of twin front Browning machine guns, this was completed at Thornaby. With more Hudsons coming on strength, 220 Squadron began North Sea patrols and Battle Flights attacking enemy airfields and shipping on the Scandinavian coast and Heligoland Bight. Airborne at 08:25 on 16 February 1940, a battle flight of three Lockheed Hudson aircraft, K, M, and V of No. 220 Squadron located the German ship "Altmark"