Complex sentence: In the 1930s its owners established the Hamburger Flugzeugbau which built aircraft before and during World War II and, shortly before the outbreak of war, became a subsidiary of its parent company and adopted its name.
Split into simpler sentences: In the 1930s its owners established the Hamburger Flugzeugbau. It built aircraft before and during World War II and, shortly before the outbreak of war, became a subsidiary of its parent company and adopted its name.