By December 1939, Johnson began his initial training at 22 EFTS (Elementary Flying Training School), Cambridge. He flew only three times in December 1939 and eight in January 1940, all as second pilot. On 29 February 1940, Johnson flew solo for the first time in Tiger Moth N6635. On 15 March and 24 April, he passed a 50-minute flight test followed by two night flights the following day. The chief flying instructor passed him on 6 May. He then moved to 5 FTS at Sealand before completing training at 7 OTU (Operational Training Unit) – RAF Hawarden in Wales flying the Miles Master N7454 where he earned his instrument, navigation, night-flying ratings and practised forced landings. After training was complete on 7 August 1940, Johnson received his "wings" and was immediately inducted into the General Duties Branch of the RAF as a pilot officer with 55 hours and 5 minutes solo flying.