During the breakthrough to the English Channel, rail networks were attacked to prevent Allied forces rallying. Greim's V. "Fliegerkorps" subjected regrouping French forces to heavy air bombardment. From 13 to 24 May, 174 French rail stations were bombed as were 186 localities, while factories were struck on 35 on occasions and airfields 47 times. Guderian's advance tore through the heart of ZOAN's area and AASF's infrastructure threatening the western airfields of ZOAE. The British abandoned France on 19 May, a day before the German army reached the Channel at Amiens. Sperrle's subordinates, Richthofen and Greim lost 47 reconnaissance aircraft in five days in a bid to find targets.