Detail - David Fowler McIntyre Window
The identity of the figure on horseback at the top of the window is unclear. If the window were in an English church then we might think of St George but that seems unlikely in this case.
A similar figure is seen in other Church of Scotland sanctuaries.
Another possibility would be St Michael, though he is often shown with wings demonstrating his status as Archangel.
A third possibility is St James who is also often pictured on horseback. This represents claims that St. James appeared to the troops on the eve of a fictional "Battle of Clavijo" against the Moors in 844, promising to be with them riding a white horse.
The central figure is Moses presumably delivering the new covenant as scrolls and accompanied by Aaron.
Below Moses we see reference to the McIntyre family commercial interest in shipbuilding and air transport. On April 3rd, 1933 a test was made of sustained high altitude flying. One of the pilots of the two planes was David Fowler McIntyre. The historical accuracy is attested by the fact that the original cartoon showed a monoplane whilst in the window a biplane is shown, as was used in the expedition.