That Airplane!!!??

I also was interested in that airplane so I researched it. It's a Handley Page HP.42, a British aircraft. It flew the Britain to India and Africa routes from 1931 to 1939, before being impressed into the RAF for the war. There were only 4 built, and all were lost in 1940. There's a good article about them on Wikipedia.

To use Handley Page's official designation, it's actually one of four H.P.45 airliners built for Imperial Airway's "Western" (European) service where it was more commonly known as the H.P.42W ("W" for Western).  The H.P.45 carried more passengers but less baggage and also had a shorter range than the four H.P.42 models which operated as H.P.42E on Imperial Airway's "Eastern" (India & South Africa) routes out of Cairo. The eight Handley Page airliners enjoyed an enviable safety record during nine years of commercial service in the early days of civil aviation, but their slow air speed and low wing loading left them brutally susceptible to turbulence and indubitably caused more than one passenger to consider death a welcome alternative.  

All eight planes had unique names. The one in the movie, identifiable by its very visible "G-AXXD" registration, is "Horatius."  "Hengist," an H.P.45 converted to Imperial Airways Eastern service, was lost in a Karachi hanger fire, but the remaining three were used by the RAF in WW II.  Returning from France in November, 1939, "Horatius" became lost in bad weather and was destroyed making a golf course emergency landing.  One of its four-bladed props was salvaged and can still be seen at the Croydon Airport visitor center.  "Heracles" and H.P.42 "Hanno" were destroyed on the ground in March 1940 when a gale blew them into each other. The last surviving four-engined Handley Page airliner - H.P.45 "Helena" - was grounded in late 1940 after a hard landing and was condemned and broken up the following year.