As has been said - modern composite / plastic last longer if white
The black Vs brightly coloured issue =
VERY simplistically - the best one to see is a primarily a matter of range. At long range all you see is the silhouette of the ac, which is why the RAF's training ac are black. At shorter ranges where you can see colour = bright colours are the best so long as they do not blend in with the background (contrast). Sadly however. The human eye has evolved to best (initially) see objects that appear to be moving. An ac on a collision vector does not appear to move and is therefore very difficult to see until it gets orribly close. Once orribly close Vc will determine the time left to react. Its a bugger then cos even perfect look out will not be enough sometimes. It is a lot better than the heads in Lemming's Big Sky theory though.