Denver-based carrier but when I fly, they don't go where I need to go directly so it's rare I fly them.
Still, if you book through Kayak or Expedia or Travelocity or other sites, you'll have to endure a) no seat selection until check-in; b) extra fees; c) only get credit for half the frequent flyer miles.
http://www.washingtonpost.com/lifestyle/travel/frontier-is-latest-airline-to-sidestep-online-travel-agencies-with-direct-booking-discounts/2012/09/12/843aeb62-fcf9-11e1-98c6-ec0a0a93f8eb_story.html
Still, if you book through Kayak or Expedia or Travelocity or other sites, you'll have to endure a) no seat selection until check-in; b) extra fees; c) only get credit for half the frequent flyer miles.
http://www.washingtonpost.com/lifestyle/travel/frontier-is-latest-airline-to-sidestep-online-travel-agencies-with-direct-booking-discounts/2012/09/12/843aeb62-fcf9-11e1-98c6-ec0a0a93f8eb_story.html