I had only seen the latest episode of 'Chuck' and the 'Human Target' episode from the week before, so for me it was just a coincidence. Which of course violates one of the rules of Toobworld - there's no such thing as coincidence.
This deadly double life in the unfriendly skies is nothing new in Toobworld. Judith McConnell played an assassin stewardess in "Rebecca Of Funny Folk Farm", an episode of 'Get Smart'.
I can't remember which comic book this happened in, but there was a villain whose only function in superhero life was to provide the henchmen and sidekicks needed by other super-villains. Perhaps such a situation could be applied in this case; perhaps there is a stewardess school which trains spies to not only be deadly killers but to be flight attendants as well.
So Laura on 'Human Target', Tiffany on 'NCIS', and the unnamed stew on 'Chuck' may have all graduated from this school for flight assassins; they could have all been in the same class together.
And who might have been running such a school? First off, I just think it should be a brilliant but deadly female spy now out in the cold, looking to stay in the game and make money at the same time. We could either go with someone once seen on a serious show, likeTessa Phillips from 'Spooks' ('MI-5') or from a series in a lighter vein, like Honey Potts as seen in an episode of 'Spy Game'.
(If only to justify my bad subject heading pun, I'd go with Honey Potts who had one of the best fictional names in Toobworld. Ever.)