The Louisville airport is the home base of United Parcel Service and there’s always a wide variety of UPS planes including 747s – except on Sundays. Passenger traffic is somewhat limited, but the largest airlines here are Southwest and Delta/Delta Connection. Others include United Express, American, and American Eagle.
The most reliable spot to view aircraft traffic is the cell phone waiting lot. In 2019 the airport built a new cell phone/observation lot on the west side of the airport, replacing the one on the east side of the terminal loop which became additional parking for passengers. This new lot is across the street from the post office off Crittenden Dr. at the end of runway 17R. You’ll get a good view of aircraft landing on this runway which is the longest of the airport’s three runways. There is no charge and photography is best in the afternoon since you’re facing east. Most of the passenger airline traffic uses this runway.
The only other areas to see aircraft are also on the west side of the airport. There used to be a street called Crittenden Rd. that ran parallel to runway 17R/35L the entire distance but in the last few years parts of that road have been eliminated thanks to a project to build a new taxiway and ramp on the west side. There are a few business parking lots you can pull into on both the north and south sections of this road to get a view of aircraft taking off from or landing on the west runway. The only way to get to the north part of Crittenden Rd. is to go north from the airport under I-264 and turn left on Park Blvd. which will curve around back to the south and become Crittenden Rd. It dead ends at the FedEx building.