Fiery orb tracks USAF bomber on night mission; returns 30 minutes later, dumbfounding pilots.

My father, soon to reach his 90th birthday, was once a brilliant career officer and pilot in the USAF.  He flew B-17’s out of England during World War II.  He has enthralled the family for years telling of his riveting encounter with a UFO while flying on a post-war mission.  And this, coming from a man famous for skepticism!  
This round, fiery orb – resembling what one would see looking into the tail-pipe of a fighter jet taking off - suddenly appeared off Dad’s wing tip and tracked with them in the night sky, then sped  forward at technically-impossible speed.  Dad said the cockpit was lit up so brightly that it was possible to read print - it caused them both to turn to see the source of light.  My Dad and his co-pilot were so dumbfounded that neither of them spoke about what they had witnessed.  Then, the object returned 30 minutes later!  (Much detail left out.)  
Given my dad’s advanced age, I’m feeling the urgency of capturing his story before the opportunity is lost forever.  Please, make suggestions.  I take it these types of sightings are no longer considered rare, but my dad’s credentials and credibility are sterling.
PS  I am very unsure of the time, date or location of Dad's sightings.
Witness indicates that the date of the incident is approximate.  PD