She checked the boarding pass and tickets of the passengers as they boarded the plane. A few minutes later, she handed JackLocke's suicide note saying that security had found it while processing the coffin prior to it being put in the cargo hold. Later, Jack got up and walked toward Rupa, requesting to speak to the captain, after having heard his announcement. She instructed him to take a seat as she went and summoned Frank. When the plane was engulfed in the flash of light and under heavy turbulence, she was seen being thrown about the cabin. (5x06) (5x09) It is presumed she died in the crash as she is the only person from the plane not seen on the beach. If she survived the crash, it is likely she was killed alongside the rest of the Ajira 316 survivors. (6x08)
In the casting call Rupa was described as "20s, Indian (South Asian), pretty. Sweet, fun-loving professional young woman who can be tougher than she appears. Can deal with difficult customers with charm and ease...".
Rupa's clothing may be a pun to the term "redshirt" as she was wearing a red stewardess uniform at the time of her presumed death.