Flew on Pervis Youree crew. He became part of the group on August 1942 when he was flown from Gieger Field, Washington to Wendover to replace 1st Lt. Chester May (was group Bombardier), who took ill just before the group departed for Europe. He just finished training at Victorville, CA, which he was assigned to Liberators and only had a couple of practice runs. He never saw a B-17 until coming to Wendover. Horner joined Youree, Gerald Hopkins, and Harold Gaslin in August 1942 as a replacement for Lt. May. After completing his tour he went stateside for a year and was sent back to France to fly 50 missions in B-26s as a pathfinder for groups in the 9th AF.