Used-aircraft asking prices continued to fall last quarter, and were down 22.6 percent for the year, Asset Insight's latest market report shows. "Average ask price for tracked aircraft fell 6.6 percent during Q4, with all groups recording a decrease," the firm said.

The steady decline is "driven primarily by the number of available aircraft and buyer preference for higher-quality assets that, not surprisingly, command higher values," Asset Insight added. On the plus side, the spread between asking prices and sale prices narrowed in most categories last year.

Breaking the figures down by category, large-cabin business jet asking prices slid 25.1 percent last year, while the spread between asking price and sale price fell 0.2 percent, to 12.3 percent, last month versus a year ago. Midsize jet asking prices decreased 10.1 percent, while the gap to the final transaction price declined 0.6 percent, to 14.9 percent. Light jets saw asking prices decline 16.8 percent, while the gap to the final price was down 0.4 percent, to 7.7 percent. Turboprop asking prices edged down 2.5 percent, while the sale price gap dipped 0.7 percent, to 9.0 percent.

The company, which tracks transactions of about 90 "modern" business aircraft models, showed 1,710 aircraft on the market at the end of December.