This is a Chrome extension built because, wait, if there's a Google Now card for my flight - shouldn't I be able to add it to my calendar?!
Click the button on the top right when you have a card open to generate a link to add the flight to your calendar.
Pull requests welcome!
Chrome Web Store URL: https://chrome.google.com/webstore/detail/card-to-calendar/cjophbpaknpmebonbipimdelaikmhdbf