Exaggerated: Alice defects immediately after her introduction, the moment she sees Bob flying. That is, before she even takes off the ground.
Justified: Alice had a Dark and Troubled Past, leaving her no choice but to obey her father, but The Power of Love gives her courage to face her inner demons.
Double Subverted: It is then revealed that the Big Bad is not Alice's father but a Manipulative Bastard who killed her real family. Alice swears revenge and goes rogue. Bob soons finds her and offers a place in his squadron.
Deconstructed: Alice apparently falls in love with Bob, defects to The Federation... then shoots him in the aft in the climatic battle, revealing that she and her father planned all along to make Bob "The Hero of The Federation" (with Alice's careful help), then betray and kill him to demoralize the enemy.
Reconstructed: Bob survives and, realizing that he still loves Alice, resolves to "bring her back". Meanwhile, Alice has a similar realization and begins to hate her father for tricking her into sacrificing her love. The story goes on as outlined above.
Zig Zagged: Alice falls in love with Bob, defects to the Feds, then betrays Bob and leaves him for dead. Then Bob comes Back from the Dead, turns evil, and joins the Imperials. Just as Alice is about to acknowledge her feelings for him, Bob kills her father and becomes The Emperor himself. Alice in grief defects to the Feds again. But they discover that the Big Bad was never Alice's real dad to begin with, so she goes right back to Bob, who refuses to accept her defection because he actually pulling off a Silent Scapegoat plan...
Defied: Alice's devotion to her father and her country helps her overcome the temptation and she henceforth denies any attraction to Bob. She may still hook up with him after the war.
Discussed: "Did you hear, the new girl in Bob's squadron is Imperial Princess Alice!" "Well, duh, the heroes always get all the hot enemy chicks..."
Conversed: "I knew right away that Alice is gonna run over to Bob. After all, that's the only reason they'd introduce a hot girl with unquestionable morals fighting for the evil side."