The Scent of Fear

Also known as Armchair Theatre: The Scent of Fear

Aboard a BOAC plane departing an unnamed Iron Curtain country, a stowaway has convinced a flight attendant to conceal him so he can defect on arrival in London. However, a high-ranking secret police officer posing as a passenger informs her that the man she's protecting is not wanted for his politics; actually, he is a murderer.