There is a growing number of websites that claim to give you inside information on airline routes. These online travel mediators (horrid phrase, we know, but that's evidently what they are often called) include web-based travel agencies, route indexers (which merely list who flies where, but don't actually sell you a ticket), and various ventures which straddle the two. hidden europe takes a look at the mysterious world of flight information on the web.

In the last issue, we responded to an invitation from an US-based website which claims to offer definitive information on exactly which airlines fly between different airports across Europe. The site is at www.harefares.com and affects to be "the most complete and current free route indexer for the continent". Harefares asked that we review their site, which we duly did in hidden europe 21. It set us thinking about the growing number of such websites, each claiming in their own way to offer information of a kind for which previous generations might have turned to their local travel agent.

So we took a detailed look at seven websites, each offering information about who flies where. Some like Harefares and OAG claim to be fairly or totally comprehensive with respect to their particular areal coverage: in Harefares' case just Europe, and in OAG's case the entire planet. Some sites say that they focus wholly or primarily on low cost carriers, even though nowadays the distinction between budget airlines and their IATA competitors is more muted than it was a year or two back. Some of the sites we looked at merely advise who flies where, while others also allow you to book flights.