By the time the Germans invaded Norway on 9 April, 1940, Jens Hertzberg was already a long standing member of the Norwegian armed forces.
On 8th October, 1926, Sergeant Major 1st Class Erik Gutzeit Haug, of No.56 Squadron, Biggin Hill, lost his life when his Gloster Grebe Mk.II veered off the runway during take-off at Kenley.