Murder on Flight 502
Flight 502 takes off from New York City to London. At the airport, a bomb threat in the airline's first class passenger lobby turns out to be just an elaborate prank smoke bomb disguised as a more sinister explosive time bomb. In relief that the incident is just a prank Donaldson complains how this needlessly caused him stress on his weekend off work, to which the bomb technician derisively states how much more stressful the call to the bomb scare was for him because he was at a motel when he was called and thought it was his wife calling trying to reach him (implying he thought he had been caught in tryst with someone other than his wife) .
As the stress has momentarily passed this leads the assistant to Head of Security Robert Davenport (George Maharis) to fortuitously presenting him with a letter found in his desk in-box he would not have received until the next morning. The letter explains a series of murders will take place on Flight 502 before it lands. Robert Davenport (George Maharis) notifies Captain Larkin (Robert Stack) via the airline's direct radio channel. Donaldson and his team go over the backgrounds of all the passengers to find possible suspects which irratates Larkin for the lack of details causing him to be terse with an equally aggravated Donaldson who is none the happier for being talked down to while nursing a painful toothache. In the air, Captain Larkin (Robert Stack), off duty Police Officer Daniel Myerson (Hugh O'Brian), and flight attendant Karen White (Farrah Fawcett-Majors) look for suspicious passengers.
At first teen age passenger Millard Kensington (Danny Bonaduce) is suspected due to the fact he has a history with the airline as a known prankster who clogged a previous flight's toilets with 13 sponges he carried onboard. Because he is suspected of placing a the fake bomb in the first class passenger lobby in New York and the finding of the threating letter and is now on on Flight 502. After confronting the teenager regarding the seriousness of his actions and getting him to admit he did place the fake bomb in the airline passenger lobby but is apparently clueless about the serious nature of the found letter. Realizing the teenager's lack of malice Captain Larkin demonstrates he too means no harm to the boy and successfully defuses the moment when he invites him to visit the cockpit later so he can show him "How this thing practically flies itself." which the boy cheerfully accepts. He then relays a message back to Davenport that he thinks this is a red herring and requests further detailed backgrounds on the passengers as he only has names and addresses to go on from the flight manifest.
Relationships develop on board between elderly singles Charlie Parkins (Walter Pidgeon) and Ida Goldman (Molly Picon) who acts as a comic relief with her Yiddish sense of humor, rock star Jack Marshall (Sonny Bono) and Marilyn Stonehurst (Elizabeth Stack), and mystery writer Mona Briarly (Polly Bergen) and suave passenger Paul Barons (Fernando Lamas). Briarly suspects Barons is actually a criminal who got away with stealing seven million dollars from a bank, but Barons denies it.
The investigations on the ground and in the air produce several leads. It is discovered that wife of passenger Otto Gruenwaldt (Theodore Bikel) died because fellow passenger Dr. Kenyon Walker (Ralph Bellamy) was not available to help. But Gruenwaldt suffers a heart attack on board. Dr. Walker rushes to aid the dying man whom he could have fallen victim to before this moment. Captain Larkin voices his apprehension at allowing Dr. Walker to treat Gruenwaldt which Myerson concurs openly stating "it wouldn't be the first time" implying someone in his position could take advantage of the situation to eliminate Gruenwaldt. Dr. Walker turns the tables on Larkin regarding whether he should apply the life saving drug or not, telling him "Alright you make the decision.". Putting the weight of life and death on Larkin's shoulders for this patient. Larkin clearly realizing he now may be at blame for stopping the Dr. Walker from administering a life saving medical treatment reverses his decision and allows Dr. Walker to go ahead and inject the life saving drug. While doing so, Dr. Walker brazenly states to Larkin and Myerson that they wouldn't even know if he gave Gruenwaldt "too much or too little" of the drug demonstrating to Larkin and Myerson how far they are beyond their depth of knowledge regarding medical expertise.
Once the drug is administered via syringe Captain Larkin again attempts to assert his authority over Dr. Walker again by demanding he surrender the used syringe implying it may be needed as criminal evidence. Dr. Walker stands his ground and refuses to surrender the syringe in question and states that he is only answerable to "my peers and my profession" implying his Socratic oath supersedes the Captain and Myerson's legal authority. Larkin sharply replies that while Dr. Walker maybe responsible for just this one life but as Captain of the airplane he is responsible for over 250 passenger's lives which Dr. Walker again immediately cuts short when he pointedly draws the line by stating to the Captain "we each have our jobs to do, you do yours and I'll do mine".
Finally someone ventures to ask how long before they know about Gruenwaldt's survival, which he states will be in just few minutes and goes back to attending to Gruenwaldt who momentarily gains consciousness and begins to get upset that he has come to realize he might be expected to thank the same man responsible for his wife's death due to what he perceives an irresponsibility to duty because Dr. Walker failed to receive the call because he was at a party attending to his personal life and adding further injury didn't even remember the call for the life saving delicate operation Dr. Walker could have provided.
Dr. Walker cuts him short and explains that he doesn't expect anything from Gruenwaldt but only asks he try to understand that life and death situations occur daily to the extent that he can't remember them all. Gruentwaldt eventually gives grudging thanks for the saving of his life but makes it clear that he will still carry a hatred of his savior for the loss of his wife, which Dr. Walker sagely replies "then that is something which we will both have to live with.".
Ray Garwood (Dane Clark) attacks Marshall, blaming him for the death of his daughter due to an overdose. Garwood denies leaving the note, and Captain Larkin and Myerson believe him. Then an apparent break in the investigation comes when Briarly tells the captain that a priest on board may be an imposter, because he did nothing when it appeared Gruenwaldt was near death. Donaldson checks the priest out and discovers he is indeed an imposter and a known thief and thereby placing him under suspicion. Myerson looks for the priest, but finds him dead in the dumbwaiter. At this point the threatening letter's contents are revealed to the passengers. Briarly again notices that Barons seems the most fazed by the priest's death, and wonders if the two men knew each other. Soon a second murder occurs; flight attendant Vera Franklin is found dead by the co-pilot meaning the real murderer is still lurking.
Concerned that he may be at risk now Barons confesses to Myerson that he committed the bank robbery, and that the priest and Franklin were both involved in smuggling the money out of the country on the aircraft. Barons says he is the next target. Myerson agrees and pulls out a gun, proving he is the killer, having snapped when Barons escaped justice for his crime after no proof was found.
Myerson takes the passengers hostage and explains he murdered the priest and looked through the luggage of the crew and found the money in Franklin's bag. Captain Larkin makes a drastic move to distract Myerson by releasing the oxygen masks and going for the gun. In the ensuing struggle, Barons is killed, the cabin catches on fire, and Myerson is badly burned. The passengers extinguish the fire the aircraft upper deck of the Bowing 747 Just as the crisis ends. Coincidently Donaldson belatedly calls to warn Larkin about the danger of Myerson being reported by his superiors as being regarded as unstable (much to the Captain's irritation regarding the timeliness of the message). Larkin voices his frustration with Donaldson's slow methods as the flight lands safely in London.
On the ground, flight attendant White is alone with Captain Larkin in the cockpit and comes to say a final good bye and expresses her gratitude for Larkin saving the passengers but in a turnabout Larkin reveals his realization that White has conspired as the money smuggler of the stolen money. He explains how before the aircraft took off Franklin had dropped her bag, which had no money inside. Therefore, the money was put in the bag by the real guilty smuggler, Karen White. Larkin, in an ironic statement, tells White that in fact this will definitely be her last flight but not because of her originally expected honorable resignation implying she will have to soon face the authorities in London to face responsility for her actions that lead to the death of the innocent flight attendant Vera Franklin.
Garwood still visibly frustrated about the circumstances of his daughters death apologizes to Marshall. Dr. Walker and Gruenwaldt reconcile and form a new relationship with a promise to meet in the future for a game of chess. Charlie Perkins and Ida Goldman decide to share a hotel room. The elder man, Perkins expresses his concerns of implying a potentially scandalous social appearance of the unmarried seniors sharing a room and how that will come across by asking "What will they think of us?" to which a typically unshakable Ida shrugs and responds "So they'll call us swingers".
In the final scene as Larkin accompanies Myerson down an escalator to hand him off to the waiting British police. Myerson demonstrates he is clearly delusional. Stating that he and Larkin are in the "same business of protecting people". He further attempts to justify his actions claiming he will be commended for protecting the people from criminals because he brought a thief to justice when the law would not. Mired in the delusional belief that he will be vindicated he shouts back to Larkin that he will put in a good word to the authorities for the Captain get a commendation. Captain Larkin stoically looks on as Myerson is lead off by the uniformed London "Bobbies".
murder