General aviation might not be climbing out of its hole, but at least there are signs that the excavation has stopped. Business consultancy firm UBS Investment Research has reported that the inventory of pre-owned business jets for sale could be leveling off after soaring for several months. The number of pre-owned jets for sale is a traditional barometer of the overall health of business aviation. The more jets put up for sale, the worse the outlook. UBS reports that inventories are still 63 percent higher than previous levels, measured month-over-month, but the steep upward trend lessened in March to only a 1 percent increase. As much as 18 percent of the business jet fleet is currently listed for sale, according to the report. What has been even more troubling is that the largest increases in jets for sale have been among the younger members of the fleet. That has resulted in asking prices for late-model jets dropping 30 to 35 percent, said UBS. Other indications seem to hint at an upturn in the foreseeable future, largely dependent on the availability of credit. What's encouraging is the measurable rise in confidence within the financial community over the past several weeks-confidence that has led to encouraging advances in the stock market as the battered lending industry begins to make its own crawl back to above-ground level.