And that's my understanding of it as well, Danny. That, and 'keep your eyes peeled, lads'. When I first started thinking about it - the masses of aircraft, in the dark, no lights, no radios, certainly no 'air traffic control' as we now know it - I found myself wondering why there weren't many mid-air collisions. Then I thought about it a bit more and realised that actually there probably
were more mid-air collisions, but if there were no survivors from either aircraft concerned how would the authorities know the difference between an aircraft lost to enemy action, versus one lost to what was essentially an accident? With no witnesses, both would simply vanish without a trace.
I suppose though that the chances of colliding with other aircraft were somewhat lessened by everyone flying in (roughly) the same direction and (in theory) at the same speed, despite the 'concentration' of aircraft. In fact I believe the Bomber Command Operational Research scientists looked into this during the war* and decided that, if they diluted the concentration of aircraft in a stream to reduce the collision risks, the risks from what they called 'other factors' - presumably enemy action etc - would increase and the overall loss rate would in fact increase with it. So a heightened collision risk was more than offset by the lessening of other risks afforded by concentrating the bombers in a stream. Maybe it WAS the safety of the stream!
Right. Back to the 1951 New Pattern SD jacket!
Adam
*A surprisingly interesting book about this is called "The Science of Bombing", by Randall T. Wakelam.