Maddie: Code name Kittyhawk. She is Julie's best friend and narrates the second (and in my opinion) more uneventful half of the novel. She is hiding from the gestapo on a farm in Ormaie after the crash, and is simultaneously looking for Julie. She is English and has a lower middle-class background. She is passionate about flying planes and readily joins the ATA after leaving the WAAF, as it is the only part of the British air force that lets women fly planes. She is much more naive and open than Julie. She is described as having black hair (but I refuse to acknowledge this and will forever remain to imagine her as a brunette). *super spoiler alert* She kills Julie the next time she sees her after the crash because she was about to be brutally murdered or tortured by a Nazi officer and Julie uttered the words that she wanted to be her last. Maddie is extremely distraught over this but believes that she did the right thing.
von Linden: The Nazi officer in charge of interrogating Julie. He is described as attractive for an older man, and there seems to be slight sexual tension between him and Julie (although I might just be imagining things... but it really seems to be that way). He has a daughter named Isolde who is Julie's age, and Julie uses this knowledge to her advantage as she manages to prevent him from torturing her to death on one occasion by telling von Linden to think of Isolde as he watches her die. He seems to have a soft place in his heart for Julie, but his actions make it difficult for me to really sympathize with him.
There are many other minor characters in Code Name Verity, but I would have a hard time writing a whole lot about each of them and their contributions to the plot and characters.