Observed cigar-shaped object flying next to commercial airliner for 5 minutes, pilot commenting on it.

I was on an American Airlines flight from Springfield, MO to Tulsa, OK when the pilot announced that passengers on the right side of the aisle could look out and observe an unidentified craft flying parallel to us at the same altitude.  
I was seated at a window on that side and had a good look at the object.  
It appeared to be about a half mile away and about 200 feet long and 15 feet high.  
The pilot further said that attempts to make contact with the object were unsuccessful but that Tulsa airport radar had verified the presence of the object.  
After about 5 minutes, the object moved away quickly away from us, staying at the same altitude.  It did not rotate to show another shape but appeared to be moving sideways.  There was a single row of white or yellow lights from end to end of the object, halfway from top to bottom.  
The sky was at dusk with the end of sunset taking place about the same time.
One of two intriguing reports from the 1950's submitted by this witness.  Other report is from Arkansas for April 15, 1950.  PD