SYRACUSE, Kan. -- In a tough job market for the aviation industry, demand for one niche is booming: crop-dusting. But if you're an aspiring pilot like Ben Peterson, you've got to get past guys like Dusty Dowd.

Nearly every move Mr. Peterson made at the controls of the 1947 Piper Super Cruiser, used for training, elicited critical shouts from Mr. Dowd, who was showing him the ropes. First Mr. Dowd, 58 years old, the owner of Syracuse Flying Service Inc. and a virtuoso crop sprayer, told his student to stop looking at instruments...