Håkan Sundberg served as a pilot in LeR 3.

He served in Finland from 19 February to 2 April 1940. During his time in Finland he also served in LeR 2.

Nothing more is known about his service during the Winter War.

Sources:
Article by Eino Ritaranta in "Suomen Ilmailuhistoriallinen Lehti" no. 1/1996 kindly provided by Carl-Fredrik Geust
Additional information kindly provided by Carl-Fredrik Geust