How can I book a reservation using ITA Software? I found an airfare from BUF to STT that involves two airlines (US Air and Cape Air) so I cannot book this fare directly through US Airways. If I contact a travel agent, will he or she be able to assist me? I never use a travel agent, so I'd have to call one randomly...

ITA often advises folks to use a TA to book more complicated itineraries.

Yes, a TA should be able to help you.

ITA is not a booking service.

You can try booking through USAir using whatever "all carriers" options they allow on their "advanced options" screen or whatever it's called. Otherwise you ought to be able to have USAir book it provided you make a phone call to them rather than doing it online. As with travel agents, you may need to pay a fee for this service - most online bookings are "free" while phone reservations usually come with a price.

Before you do so, print out the "detailed fare rules" info on the ITA screen - the various booking codes are key to getting the lowest fare.

If you click on the "details" or whatever, from the itinery on the ITA page, it explains to you to supply the special codes to the travel agent. The codes are listed in the details of the trip. If I remember, ITA advises you to email or print out the codes for the travel agent.

Thank you all! I called US Air and they quoted me a fare of $507. ITA quotes a fare of $447. Perhaps I wasn't giving US Air the right information because if I use US Air's website to price out BUF to SJU, then Cape Air's website to price out SJU to STT, it comes out to $453.