With a loud sputtering roar, something like Terry Mapes' own feelings at that moment, Skybird, her little blue-and-gold airplane sprang forward and taxied over the flying field, taking the air gracefully as a leaping horse, under the guidance of its youthful pilot.Terry Mapes was working off steam. Half angry, half frightened, the girl knew that a flight in her plane was the quickest way to get hold of her nerves and make her head clear for thinking what was to be done."Those boys!" she muttered between close-pressed lips. "What's happened to them now? Starting out for a flight to Paris and not even getting to Newfoundland!"Over and over again that terrifying report, "Missing," kept ringing in her ears. Allan and Syd missing! She could picture a crack-up easily for the two boys. While they knew how to handle their planes skilfully, they were inclined to be reckless and were always taking chances.