Chemical Mary (No. 143) - S8-E7
Factual error: French (and other nations) ATC rely on ground-based radar to track aircraft, not GPS from the cockpit of an aircraft. Meanwhile, whilst the aircraft that had been tampered with had compromised systems, the TCAS radar on the plane flying in the other direction would have alerted its pilots to take avoiding action.
Ogden Greeley (No. 40) - S8-E8
Factual error: During the scene in a London bar, the emergency exit sign is red (and not green as required by UK law). The signs adjacent to the toilets are unlike the ones regularly seen in the UK, as are the US style light switches and a 110v power outlet in the ladies' toilets.