You're doubtless already familiar with Go, Buzz, bmibaby, easyJet and the Irish budget airline Ryanair. But Britain is not the only country to operate no-frills airlines, and if you're thinking of taking an internal flight within the US, Canada or Australia, you should know about them - particularly as the big name sites will usually only offer you a much more costly flight on American, United or their ilk. You can also use them to save money if you've found a cheap ticket to a big hub like LA but really want to be in New Mexico. Beware the possible pitfalls, however: some sites will only accept credit cards issued in the US on their websites. And make sure you have a currency converter to hand: xe.com is a good choice. All prices quoted are for May 1.
Opodo
I mention Opodo as a warning rather than a recommendation. Last month, I was delighted to find a one-way flight from New Orleans to San Francisco there for a very reasonable £109. (Other sites had quoted anything from £450 upwards). I saved it in an itinerary and returned to book it, but to no avail: the site simply refused. It was only after a call to customer services that I discovered why. Not all the airlines which list their fares on Opodo's database allow the company to sell their tickets. "This is an issue that our technology department is working to resolve urgently," explains an Opodo manager.
Frontier
San Francisco-Orlando single £113
So I took my custom directly to the airline, Frontier. Unfortunately, Frontier will only accept US credit cards on its site, which meant I had to call Denver to book the flight. Still, the booking was quick and marvellously efficient. Frontier, which was set up in 1994, flies between 25 US cities and connects in Denver.
Jet Blue
New York to Burlington (Vermont) single £37
JetBlue prides itself on offering a more sophisticated service than most low-cost airlines, including leather seats and live satellite TV.
Southwest
Los Angeles to Tucson (Arizona) single £42
Southwest is one of the original low-cost airlines. It was launched in 1971 - the early ad campaign can be admired online if you enjoy such things - and now serves 57 cities.
Virgin Blue
Brisbane-Darwin single £85
Yes, Sir Richard's business interests extend way beyond British trains and Virgin Atlantic. He also operates a network of internal flights in Australia. The site is easy to use and as brightly coloured and bombastic as you might expect.
WestJet
Vancouver to Saskatoon single £59
Westjet was established six years ago and flies between a number of Canadian cities, including Ottawa, Edmonton and Winnipeg (but not Toronto). It's particularly useful if you want to explore the country's interior.
