AircraftPost.com said pre-owned midsize and large-cabin business jet transactions in the first quarter climbed 23 percent compared with a year ago. Meanwhile, corporate aviation information provider JetNet’s first-quarter figures show that pre-owned business jet inventory levels are dropping, now down to 15.6 percent from 17.7 percent last July. However, a record low 555 aircraft were sold in the first quarter, 40 fewer than the same period last year.