Yeah, "Passenger" (乗客) there reads "Jyoukyaku" in Japanese, which has similar pronunciation with "Shoukaku". Actually Zuikaku says something that's usually translated as "Shoukaku-nee" here. But with the pun, typing "Passenger-nee" would be confusing, so I used "sis" instead.
Today we're taking a trip to Sasebo via airplane.An aircraft carrier riding on airplane isn't bad, eh? Zuikaku.(Shou) Zuikaku? you look pale.(Zui) I-Is there an "etiquette bag"? *blargh*Sis' Jyoukaku!Jyoukyaku means passenger.