According to his book, he was in the Air Corps !
From 'Step Together!' - Ireland's Emergency Army 1939-46' As Told By It's Veterans' by Donal MacCarron.
"....one foolhardy competition that Mac, Denis 'agus me fein' engaged in for a time was over a wooded spot out of view of Rineanna where we spun the Cadet (C7) from 2000 feet to see who could get in the most turns before pulling out. It was Denis, I think, who had a very near miss, hitting the leaves on recovery - but winning. I recall dropping message weights for a local girl friend in a back field in Raheen. On at least two occassions, I landed in the Cadet in a field, and recall taking one of her two brothers fro a short spin over the Shannon nearby."