The E! star and the rapper were photographed separately at LAX airport on Wednesday evening.
The brunette beauty kept it casual for the flight, sporting a red plaid top with a black T-shirt and holding a big red handbag. Kardashian wore her sunglasses inside and kept her head down as the duo made their way through the terminal.
Montana surrounded himself with his entourage and tried to cover his face with a gray hooded sweatshirt.
"Khloé adores him," a source recently told E! News exclusively. "She keeps telling everyone what a great guy he is."
However, despite the 29-year-old's growing closeness to Montana, those close to the Keeping Up With the Kardashians star "think it's a rebound," the source continued.
The pair has been nearly inseparable lately—hitting Sean "Diddy" Combs' son's birthday party together, grabbing a meal with Kourtney Kardashian and Scott Disick, watching the Lakers game at Philippe Chow restaurant and even enjoying a dinner date at Crustacean restaurant Monday night. Still, a source tells E! News, "no one thinks this will last."
But this doesn't mean there is hope for a Khloé and Lamar Odom reconciliation. "That is done, finished," the source added. "She would never."