I've know for a while that Frontiers website was quirky, however I've been able to accomplish what I needed and it does seem to be getting better little by little.

One of the weird things is that it apparently lists you upcoming flights in the order they were booked and not on the date they are to be flown. This morning I went to check in for a flight later today and my flight was not listed in my profile.

I had to dig back into my confirmation emails to look up the confirmation number.

Another thing I've noticed is that there is no way to return to the home page after you have gone to another page on the site.