Same goes to British Airways, many people fly on BA and have earned miles, these miles are called Avios. A friend of mine discovered yesterday that from a family holiday she had 20K Avios in her account sitting. This is two return tickets to Paris or Berlin :).
If you shop online for clothes, food, amazon, tools etc then you can visit the Avios e-store and earn them on every transaction. I bought a camera from John Lewis, same price and everything just earned Avios as well.
Petrol is a good as well especially if you combine it with the American Express Card as well. You can fill your tank up in Tesco, earn Clubcard points and double American Express points.
If you are travelling many hotel chains give you Avios points or you can transfer your Hotel points to Avios. I stayed for a week in Dubai last year and earn Avios equivalent to 2 return flights to Europe. Many times these hotels and schemes will have promotions for 20% to 300% more Avios if you convert to them. It is a no brainer that this is when you have to convert, unless you need your Avios to travel. Thomas cook and Thomson have an excellent earning rate of Avios through the e-store.
The possibilities are endless on how you can earn and use your Avios. I know people who have been around the world for only £1500 by spending their Avios to Travel.
I hope this as an easy introduction, if you have any more questions please comment or drop me an email. 🙂