O.K., here is the answer:
The Iaccaci brothers, August Thayer and Paul Thayer (same middle name,too)
Both flew for 20 Squadron
Both flew Bristol "Brisfits"
Both scored 17 credited victories
Both were awarded the DFC
Paul scored his first victory on May 18, 1918, August on May 19, 1918
Both scored their last victories in September 1918
Finally, both lived through the war
They flew their own aircraft and never flew in the same plane. Each used 7 or 8 different observers during their careers.
I just have always been fascinated by the seemingly identical careers these men had and the fact that they were brothers makes the similarities all the more astounding. -- Al