On Jun. 13, 1943,  60 B-17s escorted by P-47s, Bombed Kiel in Northwest Germany on the Baltic Sea. As soon as the P-47s turned for home, the AAF bombers were attacked by Luftwaffe interceptors and 22 of the 60 B-17s were shot down.

On Mar. 10, the P-47 became operational when several made a fighter sweep over Europe. On Apr. 8, two additional P-47 groups became operational. In May, P-47s began flying escort for AAF heavy bombers. However, P-47s still did not have sufficient range to fly penetration and withdrawal escort all the way to targets deep in Germany. This often led to disastrous results.