"Where then are the wrecked vessels?" asked Hart. "No, Jack, electrical storms do not destroy huge air liners and then suck them out into space beyond our vision. These two ships are no longer on the surface of the earth, else they would have been long since located. The magnetic direction finders of the transportation people have covered every inch of the United States, as well as Mexico and Canada."
"Of course they might have been carried halfway around the world by a wind of unprecedented velocity." I commenced a silly argument in favor of the theory that the elements had accounted for the two vessels, but was interrupted by the mounting roar of great engines throbbing overhead.
"Hurry up there, George!" shouted Hart. "It's the SF-22 coming in. We have to be ready for the take-off in five minutes!"
He hastened to take George's place at the washbowl and all was activity within the confines of our hangar. George and I left the office and went out to the landing field, which was now brilliant with the glare of floodlights. The Pioneer had been trundled into the open and stood ready for the flight. Not a hundred feet above the field, the huge silver moth that was the SF-22 swept by in a wide circle that would bring her into the wind. The roar of her engines died as she swung out of the circle of light into the surrounding darkness.
The crowds which had gathered to witness her landing buzzed with excited comment and speculation. Her nose brought slightly up, she dropped to a perfect three-point landing, the brakes screeching as she was brought to a standstill at the hangar of the transportation company.
"Come on now, you fellows," came the voice of Hart Jones from the hangar entrance, "there's no time to lose. The Pioneer takes off immediately after the big fellow."
We hurried to the waiting ship, which seemed like a tiny toy when compared with the giant SF-22. I had observed very little of the construction of the Pioneer, but I could now see that she was quite different in design from the ordinary plane. A monoplane she was, but the wing structure was abnormally short and of great thickness, and there were a number of tubes projecting from the leading edge that gave the appearance of a battery of small cannon. The body, like all planes designed for travel in air-level six, was cigar-shaped, and had hermetically sealed ports and entrance manholes. A cluster of the cannon-shaped tubes enclosed the tail just back of the fins and rudder and, behind the wing structure atop the curved upper surface of the body, there was a sphere of gleaming metal that was probably three feet in diameter.
Before I could formulate questions regarding the unusual features of the design, we were within the Pioneer's cabin and Hart Jones was engaged in clamping the entrance manhole cover to its rubber seat. A throbbing roar that penetrated our double hull attracted my attention and, looking through a nearby porthole, I saw that the convoy of army planes had taken off and was circling over the SF-22 in anticipation of her start. Trim, speedy fighting ships these were, with heavy caliber machine-guns in turrets fore and aft and normally manned by crews of twelve each. The under surfaces of their bodies glistened smooth and sleek in the light from the field, for the landing gears had been drawn within and the openings sealed by the close-fitted armor plate that protected these ordinarily vulnerable portions when in flight.