A difficult question, Jeremy.
He wore the uniform and flew many successful, very dangerous missions...and he would have to be considered a hero in that respect.
However, he also had an obligation (which he was very well aware of when he accepted the mission to be a U-2 pilot) not to let himself or his aircraft be captured by the enemy.
Tough call. While I wouldn't say he was a traitor, I would have to say that he did not completely fulfill his duties. The Russians learned a great deal about the U-2 and it's capabilities because Major Powers did not (or could not) destroy the aircraft and use the infamous needle.
-71 made a lot of that a moot point, but the usefulness of the U-2 against the Soviet target was forever compromised after Major Powers' failed mission.
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