For such a deeply personal, introspective poem (it's kind of like a meditation, isn't it?), there are a whole lot of other people floating around in this poem. First, we've got the people the airman fights, then those he guards, then the poor people of Kiltartan. But wait, we're not finished yet. Add to that the public man and the cheering crowds, and you have a poem provides a stark contrast between the lone airman, and the crowd of folks he leaves behind on the ground. He's truly his own man up there, flying to the beat of his own drummer (if you can picture that).
Line 3: In an odd turn for a soldier, the speaker doesn't hate those he fights.
Line 4: Odder still, the speaker doesn't love those he guards. This line is almost identical to line 3. It starts the same way, so we've got some anaphora going on.
Lines 6-8: We learn that the airman's true countrymen are the poor of Kiltartan Cross, a place in Ireland. The speaker privileges the local over the national. It's like saying "I'm a Texan, not an American." There's a good amount of internal rhyme in these lines as well, especially with the long and short E sounds (short E: "countrymen," "end," "them"; long E: "leave," "before").
Line 10: Neither the public man, nor the cheering crowds, were factors in the speaker's decision to go to war. It sounds like he's definitely taking responsibility for his own decisions, that's for sure.