On 3 September 1939, the day Britain declared war on Germany, Marix was granted the acting rank of air vice marshal.
He was promoted to the temporary rank of air commodore (acting air vice-marshal) on 1 January 1940, and a week later was appointed Deputy Senior Air Staff Officer of Coastal Command.
On 11 July 1940 he was made a Companion of the Order of the Bath "in recognition of distinguished services rendered in recent operations".
On 24 March 1941 he became Air Officer Commanding, No.
18 (Reconnaissance) Group.
On 10 February 1942 Marix relinquished his acting rank of air vice marshal, and on 10 March became Air Officer-in-charge of Administration of Ferry Command, which took over the ferrying of new aircraft from factories in North America to the UK from the civilian Atlantic Ferry Organisation.
On 11 June 1942 Marix received his third mention in despatches, and on 1 October 1942 his temporary rank of air commodore was made substantive.

On 25 March 1943 Ferry Command was redesignated No.
45 (Atlantic Ferry) Group within the newly created Transport Command.
On 1 April Marix was appointed Air Officer Commanding, No.
45 Group, and granted the acting rank of air vice-marshal for the second time on 11 April, which was made temporary on 1 June.
On 12 June he was awarded the Order of Polonia Restituta (2nd class) by the President of the Republic of Poland.
As AOC, No.
45 Group, Marix was based at Dorval Airport, Montréal, Canada.
The Group comprised two ferrying wings, No.
112 (North Atlantic) Wing and No.
113 (South Atlantic) Wing, a Training Wing and a Communications Squadron, in all employing over 5,000 service and civilian personnel.
On 4 January 1945 Marix arrived in Australia on an inspection tour of a new trans-Pacific ferry route from Canada to Australia, run by No.
45 Group in collaboration with the American Air Transport Command, in anticipation of increased activity in the South West Pacific theatre.
He commanded No.
45 Group until replaced by Air Vice Marshal George Beamish on 15 June 1945.
Marix then served at the Headquarters of Transport Command, until retiring from the RAF on medical grounds on 6 December 1945, retaining the rank of air vice marshal.

Air Vice Marshal Marix died on 7 January 1966.
In May 2016 his medals, logbook and service revolver were donated to the RAF Museum by his 91-year-old daughter-in-law Yvelene de Marcellus Marix in Washington D.C.
On 3 September 1939, the day Britain declared war on Germany, Marix was granted the acting rank of air vice marshal. He was promoted to the temporary rank of air commodore (acting air vice-marshal) on 1 January 1940, and a week later was appointed Deputy Senior Air Staff Officer of Coastal Command. On 11 July 1940 he was made a Companion of the Order of the Bath "in recognition of distinguished services rendered in recent operations". On 24 March 1941 he became Air Officer Commanding, No. 18 (Reconnaissance) Group. On 10 February 1942 Marix relinquished his acting rank of air vice marshal, and on 10 March became Air Officer-in-charge of Administration of Ferry Command, which took over the ferrying of new aircraft from factories in North America to the UK from the civilian Atlantic Ferry Organisation. On 11 June 1942 Marix received his third mention in despatches, and on 1 October 1942 his temporary rank of air commodore was made substantive.
On 25 March 1943 Ferry Command was redesignated No. 45 (Atlantic Ferry) Group within the newly created Transport Command. On 1 April Marix was appointed Air Officer Commanding, No. 45 Group, and granted the acting rank of air vice-marshal for the second time on 11 April, which was made temporary on 1 June. On 12 June he was awarded the Order of Polonia Restituta (2nd class) by the President of the Republic of Poland. As AOC, No. 45 Group, Marix was based at Dorval Airport, Montréal, Canada. The Group comprised two ferrying wings, No. 112 (North Atlantic) Wing and No. 113 (South Atlantic) Wing, a Training Wing and a Communications Squadron, in all employing over 5,000 service and civilian personnel. On 4 January 1945 Marix arrived in Australia on an inspection tour of a new trans-Pacific ferry route from Canada to Australia, run by No. 45 Group in collaboration with the American Air Transport Command, in anticipation of increased activity in the South West Pacific theatre. He commanded No. 45 Group until replaced by Air Vice Marshal George Beamish on 15 June 1945. Marix then served at the Headquarters of Transport Command, until retiring from the RAF on medical grounds on 6 December 1945, retaining the rank of air vice marshal.
Air Vice Marshal Marix died on 7 January 1966. In May 2016 his medals, logbook and service revolver were donated to the RAF Museum by his 91-year-old daughter-in-law Yvelene de Marcellus Marix in Washington D.C.
Reginald Marix