The aircraft used in most of the episode is the unpopular and short-lived Convair 880. However, at various points in the episode - and especially in the initial moments - other aircraft are used as substitutes. On approach, a Convair 880 is shown, followed by closeup of main gear extension on an unidentified high-wing passenger aircraft, shot out of the window. A United Airlines 747 in its original livery is then shown on final approach, followed by a closeup of the main body gear of a 747 at touchdown. (This is accompanied by the de rigeur touchdown sound used in most 1970s TV shows.) Cockpit video also appears to be from a different aircraft type, but the interior video does seem to have been shot in a Convair 880.
The hijacked aircraft, alternately called Alpha Bravo 6367 and PLL 636, is told to land on "Auxiliary Runway Number 4". Although Los Angeles International Airport has four runways, none is named runway four. Runways take their names from their directions, and in reference to adjacent runways of similar direction. All four runways at LAX face the same direction, and when approached from the sea as in the episode, are referred to as 6L, 6R, 7L, and 7R.
The disease present in the passengers was repeatedly referred to as being viral, when Rickettsia species are bacteria. As no clear diagnosis was given and the fact that the plane had been in the Pacific, it is reasonable to assume that the cause for alarm was an epidemic of (likely) typhus fever which is caused by a species of Rickettsia.
When the terrorist refuses the inoculation, he proves he isn't lying by injecting himself. But in order to do this he sets the syringe down (instead of handing it to Sonya) while rolling up his sleeve. By laying it down it would no longer be sterile, something a doctor wouldn't do.