[Jasber]

What about Open Travel (http://www.opentravel.org/)? Its a format being supported by some of the major players in the travel industry: http://www.opentravel.org/Join/Members.aspx

I am working in a startup that aggregates rental car rates, similar to Tripeedo using OpenTravel. Its all XML based, and can be a PITA--but the result are a better product and a better user experience.

[potatolicious]

I doubt this sort of scheme will gain real traction - much of the airline industry's scheme involves building consumer loyalty (e.g. "I always fly with XYZ Air, they have decent prices and I don't have to hunt around hard to use websites"). An open API destroys this, and makes airfare even more of a commodity than it already is. I've heard anecdotal stories about Kayak being constantly blocked by the sites they scrape.

[Jasber]

Sites like Tripeedo are not geared towards loyal customers-they're geared towards bargain shoppers.

OTA is gaining real traction. By my count about 1/3rd of the companies listed on Tripeedo are members of OTA, while many more unofficially support some derivative of it. Most of these companies don't have open API's--they are very private and require NDA's and partnership agreements.

There are systems in place to handle use-cases like this. API's are in place for travel agents to search available rates and creating bookings. This is essentially the same concept.

Kayak is justifiably being blocked because they're scraping sites. If they had partnership agreements in place this wouldn't happen.