‘Airplane and constellations’ is the terse Gibbons description of this stamp commemorating the 75th anniversary of the Universal Postal Union (UPU)*, but which constellations are they supposed to be? 

Some clues can be obtained by looking at the UPU symbol in the centre of the stamp. This is encompassed by two circles representing the equator and the meridian, bearing the compass directions N, S, E, and W. Squashed in on the northern horizon is a flattened representation of the seven stars of the Plough, while to the south are four stars forming a stylized Southern Cross. The pattern to the east is supposedly Orion, although only the southern half is shown, from the belt down to Rigel. The pentagon of five stars to the west is intended to be the bow and arrow of Sagittarius. 

The design looks as though it was influenced by the Air France posters drawn by the artist Lucien Boucher (1889–1971), particularly this one. 

*Note: The name Universal Postal Union was adopted in 1878, although the organization was formed as the General Postal Union in 1874. The 75th anniversary occurred in 1949, so these stamps were four years late!