At peak times, I found that Louisville International Airport (SDF) is a great airport to be viewing airplanes. Although traffic can be dull, when you get to the airport at the right time, it is amazing. The big boy in town is UPS, which has their international operation here at SDF. Two new parallel runways were added within the last four years and since expansion around the airfield was almost impossible, all of the infrastructure (i.e. roads, buildings, etc.) was squeezed together within the boundaries permitted. Which means that the airport boundary line runs right next to roads surrounding the airport. As mentioned before, the airplanes coming into Louisville can not be compared to what we find at JFK or LAX, but most of the time we have four or five UPS 747s, several 767s and many more sitting on the ground ready to go. Unfortunally, commercialy the biggest jets are Delta's 727s, except during Kentucky Derby, when we find Delta using 757 equipment. The starting points of runways 35R and 35L can be viewed from less than 200 feet, and seeing a 747 that close is amazing.