Business jet shipments worldwide increased 12 percent in the first quarter of this year over the same period last year, according to a report released Friday by the General Aviation Manufacturers Association (GAMA). The association said that the industry delivered 211 aircraft between January 1 and March 31, compared with 188 in the same period last year. Turboprop deliveries were also up, from 59 in the first quarter of last year to 77 this year. Total aircraft shipments worldwide, however, were down slightly, to 842, due to a weak piston segment compared with 847 in the same period last year. Total billings were strong, though, up 11.3 percent to $4.5 billion. Cessna was the overall leader in the first quarter, delivering 81 turbine aircraft. Hawker Beechcraft (formerly Raytheon) and Bombardier were second and third, with 60 and 56 deliveries, respectively. Hawker Beechcraft and Pilatus were the most improved; the former shipped almost 40 percent more aircraft, while the latter shipped 81 percent more PC-12s.