Why This Matters When You Book a Flight
If you’re flying from a smaller Indian city to an international destination — say, Lucknow to London, or Pune to Toronto — there’s almost never a direct flight. You’ll connect through a hub, and your journey will likely involve two different airlines.
How those two airlines cooperate determines:
- Whether your bags go straight to your final destination or you have to collect and re-check them
- Whether you’re protected if you miss your connection due to a delay
- Whether you can earn frequent flyer miles on the whole journey
- Who is responsible if something goes wrong
The two main types of airline cooperation are codeshare and interline. Here’s how each works, with real examples for Indian travellers.
Codeshare Flights: One Flight, Two (or More) Flight Numbers
A codeshare is a specific arrangement where two airlines sell seats on the same physical flight. One airline operates the flight — providing the aircraft, crew, catering, and ground handling. The other airline markets the flight — selling it under its own flight number and brand.
How It Works — A Real Example
You search for Delhi to London on HappyFares. You might see two results that look different but are actually the same flight:
| Flight Number | Route | Operated By | What You Experience |
|---|---|---|---|
| Air India AI 111 | Delhi → London Heathrow | Air India | Air India aircraft, crew, meals |
| United Airlines UA 8285 | Delhi → London Heathrow | Air India | Air India aircraft, crew, meals |
Same aircraft. Same crew. Same departure gate. Same departure time. The only difference is the flight number on your boarding pass. If you book UA 8285, you still board an Air India plane. United is the “marketing carrier” — it sells the seat. Air India is the “operating carrier” — it flies the plane.
Why Airlines Do This
- For the marketing carrier: United can offer “Delhi to London” in its system without actually flying that route. A United customer in Chicago can book a through-itinerary Chicago → London → Delhi, all under United flight numbers, even though the London–Delhi leg is flown by Air India.
- For the operating carrier: Air India fills more seats on its Delhi–London flight because United is also selling tickets for it.
- For you: More booking options. You might find a better price or more convenient connection when booking through the marketing carrier.
What You Need to Know About Codeshare Flights
| Aspect | What Happens |
|---|---|
| In-flight experience | Determined by the operating carrier. Their aircraft, seats, meals, entertainment, and crew — not the airline you booked with. |
| Baggage allowance | Generally follows the marketing carrier’s rules on your ticket. But cabin baggage dimensions may differ — check the operating carrier’s limits too. |
| Check-in at airport | Usually with the operating carrier’s counter. If you booked United but the flight is operated by Air India, go to the Air India counter. Confirm beforehand. |
| Delays and cancellations | The operating carrier handles rebooking and ground arrangements. Your refund claim goes through whoever sold you the ticket. |
| Frequent flyer miles | You can usually earn miles with the marketing carrier’s loyalty programme. Earning rates depend on fare class — some deep-discount codeshare fares earn reduced or zero miles. |
Indian Airlines and Their Codeshare Partners
Air India — Codeshare Partners
Air India has extensive codeshare agreements through its Star Alliance membership and the Tata Group restructuring:
- Lufthansa, Swiss, Austrian Airlines (Lufthansa Group — nearly 100 codeshare routes across 12 Indian and 26 European cities)
- United Airlines (US routes)
- Singapore Airlines (Southeast Asia and Oceania)
- ANA — All Nippon Airways (Japan)
- Ethiopian Airlines (Africa)
- Air Canada (reinstated December 2025)
- Icelandair
IndiGo — Codeshare Partners
IndiGo is not part of any alliance but has been aggressively signing codeshare deals to connect its massive domestic network with international carriers:
- Turkish Airlines (first codeshare partner; bilateral free-flow codeshare)
- American Airlines (extends to 29 Indian cities)
- Qantas (connects 22 Indian cities via Delhi, Bengaluru, and Singapore)
- British Airways
- KLM (30 European destinations from Amsterdam)
- Air France
- Qatar Airways
- Japan Airlines
- Delta Air Lines (via Amsterdam and Manchester for US/Canada routes)
- Virgin Atlantic
- Malaysia Airlines
This means you can book a flight from, say, Coimbatore to Istanbul with IndiGo handling the domestic leg (Coimbatore to Delhi) and Turkish Airlines flying Delhi to Istanbul — all on one ticket with through-checked baggage.
Interline Agreements: Cooperation Without Sharing Flights
An interline agreement is a broader, simpler form of airline cooperation. Unlike codeshare, interline does not involve sharing the same flight. Each airline operates its own separate flights. The cooperation is about ticketing and baggage:
- Both airlines can be included on a single ticket (one PNR)
- Your baggage transfers between the two carriers without you needing to collect and re-check
- If your first flight is delayed and you miss your connection, the airlines coordinate to rebook you
How Interline Works — A Real Example
You want to fly from Kolkata to Rome. No airline flies this route direct. With an interline agreement between IndiGo and a European carrier:
- Leg 1: IndiGo 6E 123 — Kolkata to Delhi (IndiGo aircraft, IndiGo crew)
- Leg 2: Turkish Airlines TK 717 — Delhi to Istanbul to Rome (Turkish aircraft, Turkish crew)
Because IndiGo and Turkish Airlines have an interline agreement, and you booked through an OTA like HappyFares that issues interline tickets, you get:
- A single booking reference (PNR) for the entire journey
- Baggage checked through from Kolkata to Rome
- If IndiGo’s Kolkata flight is delayed and you miss the Turkish connection in Delhi, the airlines coordinate to put you on the next available flight
When Interline Protection Does NOT Apply
If you book two separate tickets — one for IndiGo and one for Turkish Airlines — you get none of these protections:
- Your baggage will NOT transfer automatically. You must collect your bags in Delhi, exit security, re-check-in with Turkish Airlines, and go through security again.
- If you miss your Turkish Airlines connection because IndiGo was late, Turkish Airlines has no obligation to rebook you. You’re treated as a no-show and may lose that ticket entirely.
This is called a “self-connection” — and it carries real financial risk. You’re essentially on your own between the two flights.
Indian Airlines — Interline Partners
Air India has interline partnerships with 109 carriers, offering connections to 800+ global destinations. Recent additions include airBaltic, Bulgaria Air, Cyprus Airways, Uzbekistan Airways, and Scoot (60+ destinations across Southeast Asia, North Asia, and Australia).
IndiGo has focused more on codeshare agreements than traditional interline, but does have virtual interline arrangements — including one with Jetstar through the Dohop-powered Jetstar Connect platform.
Codeshare vs Interline: The Complete Comparison
| Feature | Codeshare | Interline |
|---|---|---|
| Same physical flight? | Yes — two flight numbers, one aircraft | No — each airline flies its own plane |
| Single ticket? | Yes | Yes (when booked correctly through OTA or airline) |
| Baggage transfer? | Yes — automatic | Yes on single ticket; depends on agreement specifics |
| Connection protection? | Yes — airlines coordinate rebooking | Yes on single ticket; none on separate tickets |
| Miles earning? | Usually earn with marketing carrier | Earn separately on each airline’s segment |
| In-flight service? | Operating carrier’s service | Each airline provides its own service |
| Level of integration | High — airlines share the same flight | Moderate — cooperation on ticketing and bags |
| Number of partnerships | Fewer, more strategic | Broader — airlines may have 100+ interline partners |
Practical Tips for Booking Codeshare and Interline Flights
- Always check the “operated by” line. Your booking confirmation will say “Marketing Carrier: United | Operated by: Air India.” The operated-by airline determines your seat, meal, and service quality.
- Book through a single ticket — always. This is the most important rule. A single ticket (one PNR) gives you baggage transfer, connection protection, and a single point of contact if things go wrong. When you book connecting flights on HappyFares, multi-airline itineraries are issued as single tickets wherever codeshare or interline agreements exist.
- Check baggage rules for both carriers. Flying IndiGo domestic + Turkish Airlines international on a codeshare ticket? Your checked baggage allowance follows the ticket rules, but cabin baggage dimensions may differ between the two carriers. IndiGo allows 7 kg cabin bag; Turkish allows 8 kg. Pack to the stricter limit.
- For frequent flyer miles — check before you book. Not all codeshare fares earn the same miles. Deeply discounted tickets sometimes earn fewer (or zero) miles. Check the earning chart for your specific loyalty programme and fare class before booking.
- Allow sufficient connection time. Even with codeshare and interline protection, tight connections are risky — especially at busy airports like Delhi T3 or Mumbai T2. Allow at least 2–3 hours for international connections and 90 minutes for domestic-to-international at the same airport.
- Know who to call when things go wrong. On a codeshare, the operating carrier handles ground disruptions. On an interline, contact the airline operating the delayed leg. If you booked through HappyFares, reach out to help.happyfares.in — our team coordinates with both carriers.
Frequently Asked Questions
What is a codeshare flight?
A codeshare flight is when two airlines sell tickets for the same physical flight under different flight numbers. One airline operates the aircraft (operating carrier), the other sells seats under its own code (marketing carrier). You board the operating carrier’s plane no matter which airline you booked through.
What is the difference between codeshare and interline?
In a codeshare, two airlines share the same flight — one operates, one markets it. In interline, each airline operates its own separate flight, but they cooperate on ticketing and baggage so passengers can book both on a single ticket and have bags transferred automatically. Codeshare is tighter integration; interline is simpler cooperation.
How do I know if my flight is a codeshare?
Look for the phrase “operated by” on your booking confirmation or e-ticket. If the operating airline is different from the one you booked with, it’s a codeshare. For example, “UA 8285 operated by Air India” means you booked through United but will fly on an Air India plane.
Does my baggage transfer on interline flights?
If your entire journey is on a single ticket (one PNR) issued under an interline agreement, your bags are typically checked through to your final destination. If you booked two separate tickets, you must collect and re-check your bags yourself at the connecting airport.
Can I earn miles on a codeshare flight?
Usually yes. You can earn frequent flyer miles with the marketing carrier’s programme or (if both airlines are in the same alliance) with any alliance member’s programme. The number of miles depends on the fare class — some cheap codeshare fares earn reduced or zero miles.
What happens if my codeshare flight is cancelled?
The operating carrier manages rebooking and alternate arrangements at the airport. Your refund or compensation claim goes through whoever sold you the ticket. If you booked through HappyFares, contact help.happyfares.in — our team handles coordination with both airlines.
Is it safer to book codeshare or interline?
Both are safe and offer protection when booked on a single ticket. The real risk is booking separate tickets for connecting flights — that gives you zero protection. Whether your connection is codeshare or interline, what matters most is that it’s on one ticket (one PNR).
Which Indian airlines have the most codeshare partners?
Air India has the most codeshare partners among Indian carriers, thanks to its Star Alliance membership — including Lufthansa, United, Singapore Airlines, ANA, Swiss, and Air Canada. IndiGo is a close second, with codeshare agreements covering Turkish Airlines, American Airlines, Qantas, British Airways, KLM, Air France, Qatar Airways, Japan Airlines, Delta, Virgin Atlantic, and Malaysia Airlines.
When you search connecting international flights on HappyFares, codeshare and interline availability is checked automatically. Your itinerary is issued as a single ticket wherever possible — so your bags transfer and your connections are protected.
