Depending on what reference you look at its either 30% or 25% and its 1 month or 1 and 3/4 months. Either way before the POD the RLM will have about 1100 aircraft shot down. That is not in dispute. They will also recover 30% of those pilots/crew and have almost 50% captured. Also during the month of June 1940 they will gut there advanced bomber trainers ( Ju-52's ) and instructors to fill out losses. This means that only the 1600 reserved pilots waiting for new bombers after there's were decommisioned in April are available to fill out any losses until after BoF. That's the discrepancy btw. 4100 to 3100 planes ( the 1600 were from about 800+ planes decommisioned in April to be replaced with Me-109's, He 111 and Ju-88's)

Russ / Roller007