A mighty roar went up from the crowd. The field was finally clear of the passenger carrying ships. The signalman in the control tower waved his flag at Tommy. The young flyer opened his throttle, the venerable craft waggled its wings, felt the call of the skies, and rolled smoothly down the runway. Tommy took his time in getting off the field. With as little strain as possible on the ancient wings he lifted his plane into the air. The flag waved again and Ace, pushing his throttle ahead hard, flipped the tail of his ship up and went scooting after the leisurely soaring Tommy. The planes climbed in easy circles with Ace going up much faster than Tommy. They were up a thousand feet when Tim felt a tug at his arm and turned to face the narcotics inspector. "Give me a hand and we'll see what we can find in McDowell's plane," said Prentiss. They hastened into the hangar and climbed into the cabin. Tommy had given them the exact location of the hidden compartment and without wasting time Prentiss took an iron bar and smashed his way to it. With eager fingers he ripped away the splintered wood of the top and delved inside. When his hands came into view again they held small white containers. "We've got McDowell with the goods this time," said Prentiss. "When he comes down I'll arrest him. I'll turn this over to the field manager to place in his safe while I'm out getting McDowell." Prentiss turned back to Tim as he started for the administration building. "Better come along when I go after McDowell," he said. "I may need some help. Bring your friend with you." "I will if I can find him," promised Tim. "He disappeared about half an hour ago and I haven't seen him since." A commotion near the pilot's quarters drew his attention just then. Someone broke away and started running toward him. It was Ralph, staggering slightly, and holding a blood-stained handkerchief to his head. CHAPTER FOUR The Mad Pursuit Something was radically wrong and Tim, forgetting for the moment the drama soon to be enacted in the sky, ran toward Ralph. He caught his friend in his arms as he stumbled. Blood was flowing freely from a long gash on the right side of Ralph's head. Ralph was on the verge of unconsciousness but he made a heroic effort to speak. "It's Tommy," he whispered. "McDowell's slashed his chute. If he ever steps over the side he's gone." Tim's face whitened at Ralph's alarming words. Tommy's chute slashed! He glanced aloft. The planes were almost up to 2,000 feet. In a few more minutes they would be rushing headlong toward each other and Tommy would step over the side to hurl like a falling star to the ground. Tim's eyes closed to shut out the image which flashed across his mind. Prentiss reached his side. "What's happened?" "I don't know exactly," said Tim, "but McDowell's slashed Tommy's chute with a knife. Take care of Ralph. I'm going up to stop Tommy."