Ryanair has launched a new smartphone app to make bookings, but is charging for the service when its rivals offer a similar app for free.

The budget airline launched the iPhone and iPad app today, which costs £2.49 in Apple's App Store. British Airways and Easyjet allow you to book via their free apps.

You can continue to book for free via Ryanair's website. Regardless how you book, you may be subject to the airline's host of other fees, such as to pay on plastic or to check baggage into the hold.

Ryanair boss Michael O’Leary says: "Passengers can now book Ryanair flights anywhere they take their phone, day or night, ensuring that they never miss out on our lowest fares."

Martin Lewis, MoneySavingExpert.com creator, says: "Sometimes Ryanair pushes it so far the other way, I almost find myself admiring Michael O'Leary's chutzpah. 

"I don't know of any other mainstream flight or other sales-based companies which charge for their apps – most realise keeping it free works. 

"Yet I suspect Ryanair has done its homework and knows buying apps doesn't feel like real money, so if people are rushed, find the app and want to book they'll click 'buy' and it can pocket the cash. 

"Of course, the best answer is to avoid it and go online."