Ever noticed 'VT' on your flight? Here's what it stands for

The prefix marks that the aircraft has been registered in the country. It is mandatory in all countries. The registration of the aircraft is required to appear in its Certificate of Registration and an aircraft can only have one registration in one jurisdiction.

The registration is as per international laws, every aircraft must specify which country and airline it belongs to, using a unique alpha-numeric code, which is of five characters, that is in IndiGo's case, VT-IDV. In simple words, the call sign or the registration code is for the identification of the aircraft.

The Britain set the prefix 'VT' for India before the partition in 1929. The British set the code for all the colonies starting with V. However, countries like China, Pakistan, Nepal and Sri Lanka changed their codes later. While in India, the prefix has remained on the aircraft even after 90 years, which caused a lot of commotion in 2016 with BJP member Tarun Vijay saying that the registration number of Indian aircraft marks the legacy of 'British Raj'.

"The 'VT' code has a reflection of colonial rule," he said, adding "Hindustan cannot be a territory of the Viceroy. Why India is continuing with VT code? VT should be changed right away".

However, the efforts of the Indian government to change the registration code have been fruitless. In 2004, the aviation ministry had approached the International Civil Aviation Organisation or ICAO to change the code but no decision has been taken taken so far.