Reconfirm airline ticket? [duplicate]

Call the airline. You're confirming that you still plan to fly. You're also confirming that the flight hasn't been rescheduled--or finding out that it has. In the modern era of online check-in and e-mail flight status updates, confirming is a bit of an anachronism.

I only did it once, and left my ticket at the payphone I'd used for the call. This was immediately before I left on the hours-long trip to the city from which I was flying. My travel agent had to fax the airline office in town (not at the airport) to authorize them to reissue the ticket.

You would have to check with each airline to see if needed. In my experience, most airlines do not require reconfirmation (they do recommend to check that your flight is on time, though), so most likely the phrase is a just a remnant of the old days that your agent still prints.

What you should always do is to access your reservation on the airline's web site to be sure that your flights are booked into their system.