You should compare on the airline’s website as economy and business class fares appear next to each other. When you become a status holder on the airline, the airline also grants you upgrade vouchers, which you can then use to upgrade your upcoming flights. For Jet Airways flyers, these vouchers are now electronic and can be found in your Jet Airways account. In the case of Vistara, these vouchers are one-class upgrade, so you upgrade from economy to premium economy and premium economy to business class, if seats are available, at the airport one hour before the domestic flights. Coming to paid upgrades, Jet Airways, Air India and Vistara allow you to bid for an upgrade online before the flight.

Source: Mint January 08, 2019 02:48 UTC