AppleScript and system service

AppleScript

You can send a sentence to Fantastical using AppleScript. Here's an example script to create the event "Wake up at 8am."

tell application "Fantastical"
parse sentence "Wake up at 8am"
end tell

System service

Fantastical includes a system service which allows you to send text to Fantastical directly from another application. Select text from any application and select the Services submenu from that application's main menu. Now select "Send to Fantastical" and the selected text will be sent to Fantastical.