Singapore Airlines, Qantas and Cathay Pacific have frequent flyer programmes that earn you extra miles when you buy stuff via their online portals. For example, you get up to 57 Krisflyer miles for US$10 (S$13.48) when you shop at one of Krisflyer’s partner merchants, including Lazada, iHerb, Melissa and Under Armour.

Other airlines have partnered with Sephora, Asos and Apple. When you access the merchants through an airline’s website, your purchases are tracked using cookies, so you’ll be awarded the correct number of miles for your shopping. Prices are no different from shopping directly with the merchants, so there’s every reason to make your dollar work harder for you.

Don’t get your bank to waive them. You immediately get 10,000 air miles when you pay the $192.60 fee for the DBS Altitude Card or Citibank Premiermiles Visa Card. This works out to about 50 miles a dollar. To put that in perspective, you only get up to 3.2 air miles a dollar with your regular spending.

The air miles he earns on that supplementary card can be consolidated with yours in a single account. That means you pay the conversion fee to redeem the air miles just once, instead of twice for two separate cards. The Maybank Horizon Visa Signature Card supplementary card is free, while Citibank’s Citi Rewards Card supplementary card will set you back $96.30 after the first-year annual fee waiver.

Join the frequent flyer programme of an airline that’s part of a larger alliance, so you can accumulate and use your miles across its partner carriers. More than 30 airlines are part of Star Alliance, including Singapore Airlines, ANA, Lufthansa, and Thai Airways; while Oneworld includes British Airways, Cathay Pacific and Qantas. But you don’t earn air miles at the same rate on different airlines, so compare before you fly.

Most people use their miles to redeem an economy-class ticket, and then expend more miles for an upgrade to business class. Here’s how the maths works out. Say you buy a Singapore Airlines economy ticket to Tokyo for $1,865* – that ticket will cost you 90,000 Krisflyer miles. Upgrade to business class, and it will cost you another 100,000 miles. That means your ticket will cost you a total of 190,000 miles. Skip all that and simply redeem a business-class ticket – it’ll cost you just 140,000 miles.

Most airlines have a Saver award category reserved exclusively for frequent flyer programme members. These flights are cheaper, costing as much as 50 per cent fewer miles than flights under the Standard category. But seats are limited and get snapped up fast. Your best bet is to book at least five months in advance.

Pick destinations in Europe or the United States, and don’t squander your miles on a trip to Australia or Korea. You’ll get more value for long-haul flights – one Krisflyer mile redeems 2.9 cents’ worth of a business class flight to London, compared with 2.6 cents’ worth of a business class flight to Japan.

You should do that if your travel dates are flexible – you’ll get updates on all the special monthly promotions and current redemption rates – which means you’ll always optimise your air miles.

Text: Davelle Lee/Herworld