I remember hearing about these a while ago. Does anyone use them? I pay off my account at the end of every month so interest not much of an issue. How much do you have to spend to qualify for worthwhile air miles?

I have the LloydsTSB Airmiles Duo one, where you get a mastercard AND an American Express on the one account.
The mastercard one gets you 1 mile per £40 or £50 but using the Amex one gets 1 mile per tenner.
These can be used toward the flights & taxes, etc.

BA also release one. I have one of those, but it’s only been used for its cheap balance transfer rate a couple of years ago, no purchases – so I can’t fill you in on whether or you not you get any useful benefit from it.

As with all reward cards, it depends how much you actually spend on it month-to-month. If you put everything on it, leaving your cash in your account until you pay the bill when it’s due, then it may be worth a go.