Issued by Bhutan in 1974 to commemorate the centenary of the Universal Postal Union (1874–1974), this vibrant stamp beautifully illustrates the evolution of aviation in postal services. The design contrasts an early biplane with the modern Concorde, symbolizing technological advancement in global mail transport. Above, a dove carrying a letter reinforces the universal theme of communication and peace. The bold colors and thematic composition make it a standout issue from Bhutan’s innovative philatelic period. A strong collectible for both UPU and aviation-themed collections.