That "air activity," so frequently reported and so casually read in the despatches, means a good deal more than "fleets of aeroplanes darkening the sky," machines dashing and flashing around anywhere up to their "ceiling" of twenty odd thousand feet, shooting holes in and crashing each other, bombing and photographing and contact-patrolling and ground-strafing, and all the rest of it. There is just as much "air" activity, or if you measure by hours, from two to ten times as much, amongst those men whose sole occupation in life is pushing other people into the air and keeping them there until they wish to come down, and who never have their own two feet off the firm earth. The outsider hardly thinks of this, and there are even a few pilots--a very few, as one is glad to know--who are apt to forget it, while the great majority of the others don't or can't very well make much show of their appreciation of or gratitude for the sheer hard labour of the groundwork in a Squadron that keeps them afloat. I know that most pilots will be glad to have even this one little bit of the limelight turned on a class of men who deserve a good deal more than they get. No. 00 Squadron broke into the Air Activity period a full week before the Push began on the ground, but a certain amount of "dud weather" gave the pilots some intervening spells of rest and gave the Squadron mechanics a chance to catch up and keep level with their work. But in the last few days before the Push was dated to begin, the air work became more strenuous, because the Huns, evidently suspecting that something was coming off, set their air service to work trying to push over and see what was going on behind our lines, and to prevent our air men picking up information behind theirs. No. 00 was a single-seater fighting Squadron, and so was one of the ots whose mission in life was to down any Huns who came over to reconnoitre or spot for their guns, and, conversely, to patrol over Hunland and put out of action as many as possible of the Hun fighters who were up to sink our machines doing artillery observing or photographing. The more machines one side can put and keep in the air the better chance that side has of doing its work and preventing the opposition doing theirs--it is a pity many aircraft workers even now don't seem to understand the value of this sheer weight of numbers--and since both sides by this time were using their full air strength it meant that No. 00, like all the rest, was kept flying the maximum number of hours machines and pilots could stand.