Operation Rheinübung and the sinking of Bismarck
Bismarck and Prinz Eugen left Gotenhafen on May 18, 1941 and passed through the Danish Straits of Kattegat and Skagerrak. In order to hide the corsair voyage to the British, the Germans organized a theater in the Baltic in the form of a large convoy with strong security. The air force patrolled the floating convoy to, if necessary, neutralize the reconnaissance aircrafts.
If Bismarck and Prinz Eugen got into the Atlantic, it would be a disaster for the British to the greatest extent.