Business jet flight activity last month fell 19 percent from the same period a year earlier, although that was better than November’s 25-percent drop-off, according to a business jet market report issued this morning by UBS Investment Research. Flight activity for the entire year was off nearly 12 percent compared with 2007. About 86 percent of the flights UBS tracked last month were U.S. domestic flights and the remainder was international. “Business jet activity has declined sharply since mid-2008, which we expect will negatively impact the service businesses of the manufacturers and suppliers,” UBS analyst David Strauss wrote. While flight activity has declined in all aircraft categories, light jet activity saw the largest decline last month, falling 21 percent year-over-year. UBS data shows that midsize and large-cabin jet flight activity dipped 18 percent and 17 percent, respectively. “We believe the deterioration in our survey of industry professionals, increase in aircraft available for sale (including new delivery slots) and decline in flight activity presage what we think will be a significant slowing in new aircraft demand,” the UBS report concluded.