I don't travel much. So, I was surprised to see that Northwest Airlines provided a calendaring feature since the last time I booked a flight with them a year ago. Their Add a Calendar pop-up window gave me a choice of adding each flight to either Microsoft Outlook or Google Calendar. Since, I was on a PC running Windows with Outlook, I tried both options.

I wasn't logged in to Google when I tried to add the flight events to Google Calendar. Although, I was given the opportunity to login first, the attempt to add the attempt failed after the login. I tried a second time and all went well.

Google Calendar can export to the iCal format. So, I can sync the events with a Mac from there. The extra step is a little annoying. If you don't mind making your travel schedule public, you can also sync Apple's iCal directly with Google Calendar.