It feels fitting that a book that starts with an airplane ride to Vietnam ends with the airplane ride home. That's why parallelism's great. Perry and Peewee flew to Vietnam together, and now, due to a mix of injuries and medical profiles (fun!), they get to go home together.
Simple enough, right?
As much as you want to tie it up with a neat little bow, it's not really all that simple. The ending isn't triumphant. Sure, Perry and Peewee finally got what they wanted: to go home. But their reactions aren't normal, happy reactions. Peewee's body shakes involuntarily. They hold hands. It's cute, but it's also because they're like, kinda traumatized.
Now that the question of whether they'll get home alive is answered, the question remains: will they get home okay? As in, psychologically? How will they transition from war to normal society?
Chances are it's gonna be tough to switch back to civilian mode. Remember when Perry was in the hospital the first time? A bunch of soldiers commented on how weird he was. And Perry knew he was being weird, but didn't know how to snap out of it:
"There was this feeling that everything I was going to say was either too loud or too strange for a world in which people did normal things." (16.120)
It's like that dream where you're in your underwear, but real life. And with a higher chance of death.
At that point, Perry's head was still in war mode. He had gotten used to a world where people didn't do normal things, where people were focused on fighting and survival. And that was before he saw some of his worst battles of the war.
If it was hard in the hospital, it's not about to be any easier going back to the actual real world. The airplane scene that ends the novel shows just how strange Perry and Peewee's transition to civilian life feels:
"Peewee stirred in his uneasy sleep. The plane droned on. A fat man complained that they didn't have the wine he wanted. We were headed back to the World." (23.110)
Doesn't exactly make you feel warm and fluffy. Peewee's uneasy, the plane drones on. Drone is a negative sound, and makes it seem like war is still weighing heavy on the main characters' minds. Then, in the middle of it all, there's a random man whose biggest problem is the right wine. He doesn't seem to realize there's a war droning on (despite being on a plane from Vietnam. Weird).
This dude might be a peek of what going back to the world will be like—being surrounded by people whose problems seem small after all they've been through.
Perry and Peewee might be okay, eventually. But it's going to be a tough transition. And there's not even the right wine to help them pave the way.