The knitting needle in Neeley's neck alternates between piercing his shirt collar and not between shots.
After the rescue of Nora Williams, Ziva closes her mobile phone but is moments later heard talking to Ducky.
When someone has an allergic reaction, it is a common misconception that an epi pen "cures" the person. Epinephrine simply causes the symptoms to abate long enough to take an anti-histamine such as benadryl.
When Agent DiNozzo uses the EPI pen on the protected witness, he uses it upside down. The EPI-pen has an end with a gray safety cap. The black end is the end that the large needle automatically comes out when the EPI-pen is pushed into the thigh. Also there is no need to manually press the end of the EPI-pen as it is an auto-injector and will activate once pressure is applied to the thigh.
The Boeing 747 shown landing at the end of the episode has Air Force One livery.
At minute 2:10, Tony drives a Vespa without wearing a helmet. In France it is mandatory to wear a certified helmet when driving a scooter or motorcycle.
Despite knowing that the killer is on board the aircraft, Tony and Ziva continually leave Nora alone.
At around 27:50, while examining the dead sky marshal, Tony uses the quote "There's... Something on the wing... Some... Thing!" attributing this to William Shatner in The Twilight Zone episode "Nightmare at 20,000 feet". However, this line is never actually spoken in that episode of Twilight Zone, and being the Movie and TV buff that he is, he would know this.
This is simply another example of the Mandela effect.
McGee states that the plane is two hours out and Dulles is closest airport. On the great circle route from Paris there are numerous US airports on that route within easy range starting with Bangor, ME and including Boston's Logan Airport, JFK, LGA, Newark, BWI, plus the former Pease Air Force base in NH, and Andrews AFB.