you also have to consider that the mass orientation you are witnessing is only one kind of orientation flight - the mass one are the new younger bees on their first venture - if you look closely you will see loads of older bees at the entrance, rear ends outwards exposing their Nasonov glands and fanning to ensure these bees on their first venture out don't get 'lost' maybe they do it en masse as it's like a first school venture into the wide unknown, these bees will have all emerged around the same time so it may be logical that the older bees round them up and push them out.
I didn't know that even the older bees (especially the scout bees) orientate every morning on their first trip out, it's not like the prolonged orientation 'hover' of the massed young bees, but (according to Prof. Robert Pickard) the first thing these bees do at the entrance each morning is look downwards then upwards to recalibrate their internal navigation systems as to where 'gravity' is. they then take off and have a leisurely fly about the hive in ever increasing circles just to remind themselves where home is before scooting away on a scout.
Pickard recalled a pre dawn phonecall he once had from Cape Canaveral, it was not long after one of their space centre flights and the scientists had taken some bees with them just to see how they reacted and they were concerned as, even though the bees seemed OK, they weren't doing anything, just floating motionless around their container - he deduced the problem was that they couldn't detect gravity therefore just couldn't activate any of their usual morning 'pre flight checks' so they just froze, totally confused. When they came back to earth, they behaved like normal bees again.
