For the past two years, the business aviation industry has pondered when the oft-mentioned bottom of the trough in aircraft deliveries might actually be reached. In a recent JetNet iQ survey, half of the respondents believe deliveries have already hit bottom, while more than 25 percent see the industry as showing some upward momentum at last. The General Aviation Manufacturers Association (GAMA) first-half aircraft delivery numbers, released last month, suggest optimism is warranted. “We are starting to see positive signs in the 2012 shipment data,” said GAMA president and CEO Pete Bunce. “When coupled with the positive trend in the used market, we may finally be seeing the start of our recovery.” During the first six months of this year, shipments of aircraft and industry billings beat the first-half-2011 numbers, with deliveries climbing by 5.9 percent and billings up by nearly a billion dollars, to more than $8.2 billion.