Extra Bright Phony Plane Drifts

A married couple and their teenage daughter were heading back to their home in Hermosa, SD, on February 9, 1992.   
At approximately 21:30, when about eight miles south of Rapid City on Highway 79, they thought that they saw an airplane up close.  Unfortunately, it was too large, being about three stories tall and 100 feet in length.   It was also 1,000 feet from the ground (not an airplane unless it was landing) and was not making any noise (unlike an airplane landing).  
The husband got out of the car to watch but the other two stayed put.  It got within 2,000 feet of them.  A shape could not be determined since the lights along its bottom were too bright to allow them to make something out clearly.  
Said object however clearly did have three parallel, separate, long, narrow, pink colored lights which ran the length of the object, there being about ten feet between each pink line.   They watched the UFO until it moved slowly from west to east--like a hot air balloon.  It crossed in front of them on Highway 79.  
MUFON investigators had difficulty getting the rattled family to talk about what they saw.