Six years after Covid upended Indian aviation, the country’s busiest air corridors have barely moved. Passenger traffic between metro cities, Delhi, Mumbai, Bengaluru, Hyderabad, Kolkata, Chennai, is roughly where it was in FY2020. The same routes had grown at 1.8 times GDP in the four years before the pandemic.
According to a recent Kotak Institutional Equities note, the reason is not that people have stopped wanting to fly but that there is no room left to add flights.
Why Delhi-Mumbai passenger traffic has barely grown in 6 years
According to the report, the total passengers on these corridors stood at 38.8 million in FY2026, lower than the 40.7 million of FY2025, and barely above the 39.1 million recorded in FY2020. Between FY2016 and FY2020, the same routes had grown at 1.8 times GDP. Between FY2020 and FY2025, that growth rate collapsed to 0.8 times GDP.
The primary reason, as per the report, is not weak demand. It is the airport capacity. Delhi and Mumbai, which together anchor India’s busiest corridors, have been running at or near slot capacity for years. Prime windows, early morning and evening departures, are fully spoken for. An airline that cannot get a slot cannot add a flight, and thereby, a passenger is unable to book a seat.
Delhi-Mumbai, India’s single busiest route, carried 6.9 million passengers in FY2025, almost identical to the 6.8 million of FY2020, and falling further to 6.3 million in FY2026. Delhi-Kolkata dropped from 3.2 million in FY2020 to 2.7 million in FY2026. Bengaluru-Mumbai slipped from 3.9 million to 3.8 million over the same period.
Vande Bharat over flights
Another interesting observation in the report is that flights have a direct competition with Vande Bharat on the Chennai-Bengaluru corridor.
The Chennai-Bengaluru route recorded 0.8 million passengers in FY2016, grew to 1.3 million by FY2020, but had only reached 1.5 million by FY2025, a growth rate of 2.1 % annually over five years.
As Indian Railways expands its semi-high-speed rail network to more city pairs, the economics of short-haul aviation on those corridors will come under pressure. Rail offers city-centre-to-city-centre travel, avoids airport check-in times, and on routes under 400-500 kilometres, competes directly on total journey time, that too at a lower fare.
Airlines have historically benefited from the poor quality of Indian rail. As that quality improves, the competitive equation on sub-three-hour routes changes.
Shift to Tier-2: How non-metro routes are outperforming
On the other hand, Non-metro-to-non-metro (NM-NM) routes, which basically mean smaller cities connecting directly with each other, bypassing the major hubs, grew at 1.8 times GDP between FY2020 and FY2025. Total passengers on these routes rose from 10.4 million in FY2020 to 15.5 million in FY2025 and 16.9 million in FY2026. Even during the time that the report stated as challenging, FY26, these routes managed 8% Y-o-Y growth.
Cities that previously lacked direct air connectivity are now generating enough demand to sustain routes, attract frequencies and justify aircraft deployment. According to the report, the growth is being driven by rising incomes, improving surface infrastructure that makes airport access easier, and the network capabilities of carriers, chiefly IndiGo, that have invested in stitching together routes that older aviation models would have ignored.
The NM-NM segment still faces constraints: limited aircraft availability, the inability of most airline networks to serve thin routes efficiently, and ticket prices that remain high relative to incomes in smaller cities.
Virtual meetings hit Kolkata, Bengaluru air travel
According to the report, virtual business meetings are one of the major reasons behind the decrease in metro-to-metro traffic, particularly in Bengaluru. Meetings that previously required a Delhi-Bengaluru or Mumbai-Bengaluru flight are now resolved on a video call.
The report also noted that Kolkata presents a different but related dynamic. The city has seen corporate shift operations elsewhere over the past decade, thinning the business travel base that once supported strong metro connectivity. Kolkata’s metro-to-metro routes have declined across multiple corridors. Kolkata-Chennai fell from 1.4 million in FY2020 to 1.0 million in FY2025, and Delhi-Kolkata dropped from 3.2 million to 2.8 million over the same period.
India’s airport infrastructure lottery
According to the report, between FY2020 and FY2025, Bengaluru’s non-metro routes grew at 7.8 % annually while Hyderabad’s grew at 6.6 %. Both cities received meaningful airport capacity additions during this period, new terminals, expanded aprons, and additional runway capacity. The infrastructure gave airlines room to add flights, which in turn generated passenger growth.
The report also added that since Kolkata and Chennai received no comparable additions, Kolkata’s non-metro routes fell from 10.1 million passengers in FY2020 to 9.5 million in FY2025. Chennai’s non-metro traffic declined from 8.1 million to 7.7 million over the same period.
The report also noted that the new Navi Mumbai Airport and the Jewar Airport in Delhi NCR will unlock the prime slots that have been choking growth at Delhi and Mumbai
IndiGo’s quiet dominance
No airline has benefited more from the non-metro shift than IndiGo, the report noted. The airline commands 67 % of non-metro routes by scheduled available seat kilometres in the summer 2026 schedule, up 900 basis points year-on-year.
On metro routes, its share is 53 %, up 230 basis points. Competitors have cut flights through 2026 in response to fuel cost pressures. The rest of the industry outside IndiGo has dropped from 1,526 average daily flights in summer 2025 to 1,346 in summer 2026. IndiGo has held its schedule broadly steady at 1,974 daily flights, down only marginally from 2,028 last summer, the report noted.