He laughed to himself at the idea of calling the ramshackle collection of huts comprising the aerodrome as "home", then, putting the old 'bus up, he turned towards the British lines.
In spite of a load well above that for which it was constructed, the single-seater behaved magnificently. Derek took her up to nine thousand feet in order to cross the opposing lines at a fairly safe height, as far as danger from gun-fire from the ground was concerned.
Presently he caught sight of an object in the air at about a distance of two miles. It resembled an inverted bottle with a stumpy neck.
"By Jove!" he exclaimed, "if that's not a Hun with invisible wings I'm a Dutchman. Wonder if it's old Von Peilfell's 'bus? There was a rumour that the old brigand was buzzing around in this sector. And our guns are jammed, too."
Kaye also noticed the approaching aeroplane, and called Derek's attention to it. Just then the Hun, encountering an air-pocket, dived a couple of hundred feet, the sun glinting upon the transparent fabric of the broad wing-spread.
"Hun!" he bawled. "Von Peilfell's, for a dead cert."
Derek had to make up his mind. There was a choice between flight and pure bluff. He chose the latter.
The Hun and the British machines were on widely-converging courses. Already the lurid colourings on the former's fuselage were plainly visible. He was closing with the evident intention of taking stock of a possible opponent.
"I'll make him sit up," declared Derek, as he swung round and headed straight for the Hun.
Count von Peilfell—for it was he who piloted the gaudily-painted 'bus—at first made no effort to avoid a possible collision. It was not until Derek was within fifty yards that he dived steeply, and, looping, came up under the tail of the British biplane, a manoeuvre which Derek encountered by looping and practically sitting on his adversary's tail.