Describe symbolism in The Greatest Generation by Tom Brokaw

From the text:

"When she was leaving the WAVES in 1945, the staff at the Joint Chiefs of Staff allowed her to take from the metallic war maps a handful of the tiny magnetic airplanes used to mark battles around the world. Then, they were symbols of terrible battles in distant places, of the powerful struggle to preserve freedom. Now, they keep in place on her refrigerator Scottie's reminders of what's coming up next in her long, rich life"