Bismarck was stopped 12 hours out from French Ports, roughly 300 miles from port.
LW resources were actually fairly limited in western France and earmarked for co-operation with DKM in Rheinburung. JG26 was transferred to Brittany the last week of March 1941 to provide fighter aircover for Luftflotte 3. There about 15 Ju-88 LR fighter a/c aircraft set aside to support upcoming naval operations. The main strength of LF 3 was JG2, but the Luftwaffe saw fit to bolster fighter strength in that area for the navy. JG26 had few chances for combat from April through the end of May while on standby for the Navy. On the 26th (or was it the 27th but the 26th is recorded) of May the 1st Gruppe JG26 flew to its limit of 100 miles out to sea to provide CAP for Bismarck, before they were then recalled.
If Bismarck had made it to aircover, it would still be largely a matter of luck as to whether she could escape the trap set for her. The airstrikes carried out by the Ark Royal, both those that were successful and those that were not, were delivered well after sunset, in conditions of half light and poor weather the LW day fighter forces would have really struggled to have any effect. If the weather were better, or the critical period was a daylight affair the LW could mount an effective aircover operation, provided the range was not too great.
Over Crete, the specialist anti shipping units of the LW were concentrated and were effective, especially against the RN units that moved to the northern side of the island. as a generalisation, the RN was able to hold off the LW until ammunition ran low, or they remained within primary ranges for too long into the daylight. but the keys to the success in Merkur was the small range, the large numbers of aircraft and the specialist training of the air units involved. the general air force units had only very limited success over crete. in Brittany during Rheinburung, there were a few specialist anti shipping units, but the majority of units were general air force units. one could not expect near the success that the LW achieved over crete at the same time. This is borne out, incidentally, by the effort needed to sink the mashona, who like much of the RN after the battle was forced to cut through waters within LF3 range and were attacked repeatedly. despite the effort, Mashona was the only.