Question

What was the first military setback for Hitler's forces?

Answer 1

The Battle of Britain.

Explanation:

Hitler's Blitzkrieg tactics had been so successful that by June 1940 most of Western Europe including France had been conquered. This allowed the Luftwaffe access to airfields from which to mount a bombing campaign against Britain.

Goering assured Hitler that the German airforce had the capacity to defeat the RAF and pave the way for a successful invasion. However over the months from June to October 1940, the RAF was successful in repealing the German bombing strategy. The planned invasion, Operation Sealion, was postponed and in fact never took place. Britain did not fall.