K4 has about 5-6 operating at any given time, mainly late build R powered versions ,some of the last Classic's off the line with the HF aerials buried in the vertical fin like the 400, and antenna free wingtips. We have 1 or 2,Q powered ships also still in the inventory. I loved my time in the Classic, I got to fly a former Pan Am ship,a -221, and got to fly the Canarsie approach in one too,along with runs into Afghanistan, and other hot spots. I'm in the 400 now and it really is the better airplane, it flies nicer, hand flies nicer,and the avionics and auto throttles make life sweet,and simple, the 747 in general,and the -400 ERF in particular is among God's finest gifts to pilots,along with the DC3 and the 727.