WHAT'S THE MEANING OF THIS JETSTAR EMAIL?! DO THEY WANT ME TO APPLY ONLINE FOR THE CHECK IN?

These are general cut-off times when check-in closes at the airport, and to be honest you should be there at least 60 minutes before those times, as security and getting to your gate can easily account for 50-60 minutes. So arriving as late as this is not recommended. You can check-in online at a href="http://www.jetstar.com" rel="nofollow"http://www.jetstar.com/a