India and Vietnam have raised the bilateral seat cap from about 8,000 a week to more than 16,000 (Vietnam News Agency has used 16,800). The change is described as immediate. Officials also moved the limit from frequencies towards seats, which lets a carrier choose a dense narrowbody or a thinner widebody without burning the same number of 'flights'. Cirium figures cited in Indian papers put Vietnamese airlines at about 48 weekly services to India and IndiGo plus Air India at 30. First-half 2026 traffic, per Vietnamese briefings, was already up. Passengers nearly 820,400 (+15%), cargo more than 14,100 tonnes (+32%). The 2024 quota had become a ceiling. This is the second lift since then.
Air services are traditionally written by reciprocal bilateral agreements. Vietnamese carriers had used the old metro frequencies, Indian had not. VietJet and Vietnam Airlines are already named against Delhi, Mumbai, Hyderabad, Chennai and Kolkata. Sun PhuQuoc is said to want Mumbai once paper is done. Air India flies Delhi-Hanoi (from May) and daily Ho Chi Minh City, Mumbai would be an obvious second spoke if it can find hulls. IndiGo and Akasa can thicken existing links. None of that is filed until the airlines ask and the two civil-aviation authorities designate.
City pairs beyond the four metros matter more than another daily on the trunk. Ahmedabad, Bengaluru and Pune on the Indian side, Da Nang and Phu Quoc on the Vietnamese, are where a seat-based cap can change the map or sit unused. Fifth-freedom operators via a Gulf or ASEAN hub are not automatically in the room; the new seats are bilateral. Cargo rights, if they rose with the passenger cap, will show up in belly space before anyone orders a freighter.
Who gets the new seats is therefore still a contest. Vietnamese LCCs that already out-fly the Indian side, Vietnam Airlines’ A350 product, IndiGo’s frequency machine, Air India’s widebodies, and whoever can staff a night stop in a secondary city. Until frequencies are published, 16,000 is a number in a communiqué.