1944, 1958, 1955, 1967?

Is this all part of Billy’s imagination? In what year is he really stationed? Did he make it all up? Why does he suddenly travel in time? or are they really flashbacks? These are some of the questions I often ask myself while reading "Slaughterhouse-Five". 

Sometimes, when one goes through a very shocking and distressing event the most common reaction our mind has is to erase all these memories. To block them and put them in box in the corner of our minds, to never have to revive them or ever think of them again. However, what Billy Pilgrim may be going through is the opposite, the opening of that box, the peeking into what is inside it, receiving in its way flashbacks. In the movie Eternal Sunshine of the Spotless Mind there is this company which erases memories from our mind; things we won't like to remember. It similar to when someone drinks too much alcohol and doesn't remember anything from the night before, which would leave a gap or a missing part in one's memory about a specific event, the difference is that here it is voluntary. In the process of deleting his unwanted memories, the main character of the movie has to revisit and restore them in order to forget about their existence. Which although not very relevant to Billy's situation, it is similar and it could compared. He is resuscitating everything he went through in World War II, living through every detail and every sensation as if he where there again. Nonetheless, he may have confused this with time travel, and let his imagination flow to the unreal, creating the Trafalmadore. Who then provide him a different way of looking at death, something very common in war. That could be his own, personal and unique way of forgetting the past and getting through with it, by living it again unconsciously.