Hello,
From your explanation it would seem that the three airmen were on a Daylight mission as you say they were captured the same evening, this would to me suggest that they were US airmen who bailed from a bomber . Many B24's and B17's were lost on the 26th.
NARA records over 160 US airmen POW on the 26th.
see
www.armyairforces.com Databank for macr's Bomb Groups and serial details on the B17's and B24's
Bomber Command War Diary has No losses for the daylight raid on Fulda.
Alex