Ryanair blocks bookings made through screenscraping.
news.bbc.co.uk
news.bbc.co.uk
While their base ticket prices may seem incredibly low, they make their profits by tagging on extra "service fees" that appear on their website after you've begun checking out. For example, a few years ago I remember I had to pay extra for "baggage insurance", which ensures that your bags do eventually make it to their intended destination and don't get lost, something that is usually implicitly included in the original ticket price of other airlines. The UI of the Ryanair website stresses the importance of this baggage insurance with a popup window. Other airline comparison sites probably have decent UIs that don't push these options to the extent of Ryanair.
They also go to great lengths to cut any cost. I've heard that employees are not allowed to charge phones at work in order to save on energy bills. And from my experiences, their employees really don't seem to have any sort of customer service training. Or maybe they're just grumpy because Ryanair treats them so poorly.
http://en.wikipedia.org/wiki/Ryanair The Criticisms and Complaints section is actually pretty interesting.
1. They are jealous and want to gather the customer information for themselves.
2. Don't want people to know if they are truly competitive on price (apart from a few headline grabbers).
3. Don't want pricing pressure/war encouraged through open comparison.
4. They don't actually care about the customer, just their money.If you need to get from A to B for no money and you know what to expect, Ryanair's not a bad way to do it, but it's never going to be a pleasant experience.
Hilariously, the "related articles" sidebar contains "Ryanair warns of potential losses". Maybe if you didn't cancel people's reservations you would make more money.
Also, if they did, it would reduce much of the value of the price comparison sites by reducing the barrier to entry (allowing more competitor services to the market) and hence they may not want it either (rarely see a comparison site in any sector ask for APIs).
Electronic harvesting is against the rules of many big sites out there (sadly), so is it wrong comparison sites do not abide the terms and conditions of others to fix something that is broken and add value to people?
If they paid these sites a fee to compensate, would that be good or bad? (as basically it boils down to money, and one party not happy another makes money "off its back", so to speak)
That being said this is an over-reaction.