General Electric owns a 747-400 (N747GF). This aircraft is used to test new engines in-flight. For example the one in the photo: the new GE9XTM engine, which will be used on the new Boeing 777X. What a size difference compared to the CF6s of the 747!

This frame was orginally delivered to Japan Airlines in March of 1994 with registration JA8910. GE bought it in January 2011 to replace the aging Boeing 747-100 (N747GE). The 747-100 was orginally delivered to Pan Am in 1970 as 25th 747 off the line. GE bought it in March of 1992 and has used it until January 2017. The N747GE is currently on display at Pima Air and Space Museum (Tucson Davis-Monthan AFB)