I have always looked to the fare finder on itasoftware.com as a really helpful tool in checking on fares and finding good itineraries.

Now, as I am looking at that site every day for a fare to Paris, I have noticed something that I find really frustrating: "+ others"

For example, the cheapest option from Charlotte to Paris is usually on "Lufthansa + others" meaning some Lufthansa and some United flights, but not codeshares, nor the type of intinerary we can book on either Lufthansa or United. I've tried.

Why are those types of itineraries even included? Can travel agents book them?

Yes, agents can book them, and Orbitz can usually do too.

ITA searches for the lowest fares and combinations of fares. Yes of course TAs can book them, and so can most non-TAs; however it's sometimes difficult - if there's some screaming deal you can generally put it together using Expedia etc. - but time consuming.

There's a whole syntax that goes with ITA; for example if you want to use one airline on a given route, you type in e.g. From: CLT:H+ To: CDG:H+ ITA will return only Lufthansa flight numbers. It will show LH codeshares on segments where LH metal is unavailable.

There's a page available at ITA that goes over the routing syntax; it's useful to read up on it. It's an incredibly powerful tool.

Oy - Fodors and its idiot smileys. Sorry. After CLT/CDG you type in 2 colons - :: - before "LH+" which means one or more flights with Lufthansa flight numbers and no other airlines.

Ita shows the exact booking directions that can be e-mailed to a travel agent. Click on details then click on booking details and scroll to the bottom of the page. If you don't want to use a travel agent, these combo fares pop-up on sites like Expedia/Travelocity.

Many, if not most of those "+ others" itineraries are on carriers that belong to the same alliance.
And if you are concerned about booking with your preferred airline to get the max FF credit, you can do that. Just get the full booking details from the ita itinerary, book what you can online with your FF carrier then call the airline to have them add on the additional segments.

Thank you all very much. Don't know where I'd be without this board....