They are a complete waste of time and money.
    If you can waste your very precious time on endless waiting and delays, you sure can book with this airline. Otherwise, don't even think about it.
    Full Fright
    Booked a cruise for the family in Alaska and we were hoping to fly Frontier from ATL to AK but when we got to the airport the airline said flight was delayed for 3 hours. Not a big deal, but since we were connected through Denver we would miss our connecting flight. Also, happens before, not a big deal. The big deal was we would have to lay over in Denver for 2 days. We ended up being able to book a flight on Delta for twice as much and now the nightmare of trying to find out how to get linked up with our ship. Airline was very rude, dismissive and well trained in saying sorry. Which is appropriate since this airline is very, very sorry all around. Great to book if you don't care much about getting to your destination. Also don't be fooled by the prices. They charge you for both your checked and carry on luggage.
Frontier Failures
 They don't get anything right. 


 The worst airline I've flown. 


 Cheaper isn't always better. 


 Depending on which rules they choose to enforce, you can never be assured that you will be granted access to their boarding process. 


 I have never had a more infuriating, more frustrating, or more demoralizing experience traveling in my life!