Complex sentence: At the start of the war, Otto-Flugzeugwerke was supplying the German Air Force, but the production problems ended up being so great that the government agencies urged the company to nationalize its production.
Split into simpler sentences: At the start of the war, Otto-Flugzeugwerke was supplying the German Air Force, but as the war progressed so did production problems. Eventually, the government agencies urged the company to nationalize its production.