Indian Flight Number Prefixes: AI, 6E, UK, QP, IX and SG

Indian airline flight number codes are the two characters in front of the digits, and they tell you who is flying you before you read anything else. AI is Air India. 6E is IndiGo. IX is Air India Express. SG is SpiceJet. QP is Akasa Air. UK was Vistara, and it no longer flies under that prefix: since November 2024 those flights carry an AI number instead. If you have a message that says "6E 2134" or "IX 1004" and nothing else, this page is the lookup table.

What the two characters in front of the number mean

A flight number has two parts: a two-character airline designator, followed by a number of one to four digits (Wikipedia, "Flight number," captured 2026-09-27). The designator is the airline's code, from the International Air Transport Association (IATA), which runs a public code search where you can type any two-character code and see which airline it belongs to (IATA, "Airline and Airport Codes Search," captured 2026-09-27).

Two things trip people up with Indian codes in particular. First, some designators mix a digit and a letter, so "6E" is a code in its own right, not a typo for a flight number. Second, the digits after the prefix are only half the story. The same digits under a different prefix are a different flight on a different airline, so "AI 1004" and "IX 1004" are not related just because the numbers match. Always read the prefix first.

The six prefixes, airline by airline

AI: Air India. AI is the designator of Air India, the flag carrier of India, owned by the Tata Group with Singapore Airlines holding a minority stake (Wikipedia, "Air India," captured 2026-09-27). AI numbers are what you will see on Air India's domestic and international flights, and, since late 2024, on the flights that used to be Vistara's (more on that below). The Air India airline page is the starting point for anything with an AI prefix.

6E: IndiGo. 6E belongs to IndiGo, a low-cost carrier headquartered in Gurgaon, Haryana (Wikipedia, "IndiGo," captured 2026-09-27). Because the code starts with a digit, people sometimes drop it and search for the number alone, or mistake the 6 for part of the flight number. The 6 and the E together are the airline; everything after them is the flight. The IndiGo airline page is where a 6E flight number maps to.

IX: Air India Express. IX is the designator of Air India Express, the low-cost airline owned by Air India (Wikipedia, "Air India Express," captured 2026-09-27). It is a separate airline from Air India with its own code, so an IX booking is not an AI booking, even though both belong to the same group. The Air India Express airline page covers IX numbers.

SG: SpiceJet. SG is SpiceJet, an Indian low-cost airline headquartered in Gurgaon (Wikipedia, "SpiceJet," captured 2026-09-27). The letters do not spell the airline's name, so SG is easy to misread. See the SpiceJet airline page for SG flights.

QP: Akasa Air. QP is the IATA designator of Akasa Air, as listed on IATA's own member page for the airline (IATA, "Akasa Air," captured 2026-09-27). Akasa is a Mumbai-based low-cost carrier that flew its first commercial service on 7 August 2022 and operates an all-Boeing 737 MAX fleet (Wikipedia, "Akasa Air," captured 2026-09-27). Like SG, the letters do not match the name.

UK: Vistara, now retired. UK was Vistara's designator (Wikipedia, "Vistara," captured 2026-09-27). It is on this list because older bookings, screenshots and saved messages still show it, and because it changed in a way that matters when you look a flight up today. The next section explains what replaced it.

One more prefix that turns up on regional routes: 9I is Alliance Air, a state-owned regional airline that flies domestic routes under the government's UDAN regional connectivity scheme (Wikipedia, "Alliance Air (India)," captured 2026-09-27).

Two prefixes that no longer fly: UK and I5

Indian aviation consolidated two pairs of airlines in 2024, and each merger retired a prefix.

UK became AI 2xxx. Vistara ceased operations on 12 November 2024, when its merger with Air India took effect (Wikipedia, "Vistara," captured 2026-09-27; Wikipedia, "Air India," captured 2026-09-27). From that date, the aircraft Vistara used to fly were operated by Air India and identified by a four-digit Air India number beginning with the digit 2. Gulf News reported a worked example: UK 955 became AI 2955 (Gulf News, 6 November 2024, captured 2026-09-27). So if an old itinerary says UK and a number, the flight you want today, if it still runs, is an AI flight whose number starts with 2.

I5 folded into IX. I5 was the designator of AIX Connect, the airline formerly known as AirAsia India (Wikipedia, "AIX Connect," captured 2026-09-27; Wikipedia, "Air India," captured 2026-09-27). The merger of AIX Connect into Air India Express was declared complete on 1 October 2024 (Wikipedia, "Air India Express," captured 2026-09-27), and the merged airline flies under the unified code IX (Aviation A2Z, 1 October 2024, captured 2026-09-27). An I5 prefix on an old ticket points to Air India Express today.

For anything about an existing booking made under the old prefix, the airline's own customer service and its published pages are the place to check; this post covers what the codes mean, not what happens to a ticket.

Reading a number that does not look right

A few habits make a flight number hard to look up, and each has a quick check.

• The prefix is missing. "Flight 1004" on its own could be several airlines. Ask for, or find on the ticket, the two characters in front.
• The prefix is run into the digits. "ix1004" and "IX 1004" are the same flight; spaces and capital letters do not change it. "6e2134" is IndiGo flight 2134, not a six-digit number.
• There are too many digits. The standard format allows at most four digits after the designator (Wikipedia, "Flight number," captured 2026-09-27). A string like "AI 11474" does not fit that format, so something else could be mixed in: a date, a seat, a booking reference, or a digit typed twice. Go back to the ticket or boarding pass and copy the flight number exactly as printed.
• The prefix is old. UK and I5 now point to AI and IX, as above.
• The letters do not match the name. SG and QP are the usual culprits. When in doubt, IATA's code search answers "which airline is this code" directly (IATA, "Airline and Airport Codes Search," captured 2026-09-27).

Once the prefix is right, the airline page for that prefix is the natural next step: Air India for AI, IndiGo for 6E, Air India Express for IX and SpiceJet for SG.

How TrackMyWings helps

TrackMyWings™ is a live flight-tracking platform in development, India-first in go-to-market. A private beta has been running on Android since 2026-08-24, on the Play internal testing track, and public launch has no fixed date. Turning a flight number someone forwarded you into that flight's status, with gate and status alerts for the people waiting, is what the app is planned to do at launch. Until then, the airline pages linked above are the map from each prefix to its airline.

Questions people ask

Which airline is 6E? IndiGo. The digit and the letter together are the airline code, so in "6E 2134" the flight number is 2134 on IndiGo.

Which airline uses the IX flight code? Air India Express, the low-cost airline owned by Air India. Since 1 October 2024 it also carries the flights that used to be booked under I5.

Is an AI flight the same as an IX flight? No. AI is Air India and IX is Air India Express. They belong to the same group but are separate airlines with separate codes, and the same digits under each prefix are different flights.

What happened to Vistara's UK flight numbers? Vistara merged into Air India on 12 November 2024. Its flights now carry four-digit Air India numbers starting with 2, so UK 955 became AI 2955.

Which airline is QP? Akasa Air, a Mumbai-based low-cost airline that began commercial flights in August 2022.

Sources

• Wikipedia, "Flight number": https://en.wikipedia.org/wiki/Flight_number, captured 2026-09-27
• IATA, "Airline and Airport Codes Search": https://www.iata.org/en/publications/directories/code-search/, captured 2026-09-27
• Wikipedia, "Air India": https://en.wikipedia.org/wiki/Air_India, captured 2026-09-27
• Wikipedia, "IndiGo": https://en.wikipedia.org/wiki/IndiGo, captured 2026-09-27
• Wikipedia, "Air India Express": https://en.wikipedia.org/wiki/Air_India_Express, captured 2026-09-27
• Aviation A2Z, "Air India Express and AIX Connect Merger Completed," 1 October 2024: https://aviationa2z.com/index.php/2024/10/01/air-india-express-aix-connect-merger-completed/, captured 2026-09-27
• Wikipedia, "AIX Connect": https://en.wikipedia.org/wiki/AIX_Connect, captured 2026-09-27
• Wikipedia, "SpiceJet": https://en.wikipedia.org/wiki/SpiceJet, captured 2026-09-27
• IATA, "Akasa Air" member page: https://www.iata.org/en/about/members/airline-list/akasa-air/662/, captured 2026-09-27
• Wikipedia, "Akasa Air": https://en.wikipedia.org/wiki/Akasa_Air, captured 2026-09-27
• Wikipedia, "Vistara": https://en.wikipedia.org/wiki/Vistara, captured 2026-09-27
• Gulf News, "115,000 passengers impacted as Vistara merges with Air India on November 12," 6 November 2024: https://gulfnews.com/business/aviation/115000-passengers-impacted-as-vistara-merges-with-air-india-on-november-12-1.1730901379106, captured 2026-09-27
• Wikipedia, "Alliance Air (India)": https://en.wikipedia.org/wiki/Alliance_Air_(India), captured 2026-09-27