Unless you’re fortunate enough to score an upgrade from economy or premium economy to your destination thanks to an overbooked flight, there are usually only two ways to move up to a higher class of cabin. One is to upgrade your ticket on check-in, and pay the difference between the two fares in cash, but this only works if there’s a seat available, and the upgraded seat won’t necessarily be at a cheaper price. By far the most common way to upgrade, however, is using frequent flyer miles, and it’s an option offered by all the premium airlines; most will have at least a couple of seats available on a flight for mileage upgrades. Not all tickets are eligible, however, including heavily discounted ones, and you can only upgrade if you have booked your flight directly with the airline; if you used a travel agent for the ticket, you will need to go back to them to make the request. There are also different rules for each airline – and sometimes bonuses. If you’re a member of Singapore Airlines’ KrisFlyer, for example, you’ll get a 15 per cent discount on the number of miles required if you use miles to upgrade. If Emirates is your airline of choice, however, passengers can upgrade on any type of ticket as late as six hours before departure, and Silver, Gold and Platinum members can upgrade onboard the flight.