Hit road block on grandfather's career

I haven't posted in a long time.  I have received great insight in the past and am asking for more help.  I am trying to find information on my Grandfathers career and am hitting many road blocks.  He was a civilian Chief Groundschool Instructor at Falcon Field, Mesa, Az.  from 1943-1946.  I have received only his discharge papers, due to the fire in the Archives building, but I know that there is more.  Surprisingly, Falcon Field hasn't been too helpful as I do still live in Az.  His name was John Bonnell. Family 'stories' are that he also was in the OSS, but ofcourse nothing comes up on that.  Does anyone have any ideas.  I have read approx. 50/100 letters from pilots that he trained and have researched them as well.  I hope to hear form some or relatives shortly.  Any ideas would be greatly appreciated.  I would love to know more about him and his work due to the fact that he died when I was 2 and I am going off of memories of family members.  Thank you for any help I can get.
Looking (Paulla)