Just in time for the holidays, Frontier and Spirit airlines have announced fee increases for one of the busiest travel seasons of the year. 

Last month, Frontier Airlines revealed it would also increase both checked and carry-on fees by an additional $5 to $10 for flights scheduled between November 19, 2015, to January 5, 2016.  According to the Denver-based airline’s website:

"Carry On bag prices increase by $5 at booking and up to 24 hours before departure, $10 at Web Check-in, and $5 at the Airport kiosk or ticket counter; 1st Checked Bag increases by $5 at Flyfrontier.com, at booking and up to 24 hours before departure and increases by $10 at call center, web check-in, and airport ticket counter or self-service kiosk. 2nd Checked Bag prices increase by $10."

Spirit's increased baggage fees are a return of the rate hike it rolled out last year when it raised fees by $2 during the holidays. (Spirit's baggage fees regularly make our Naughty & Nice list, including the 2014 edition.)

Customers traveling on Spirit from December 16, 2015, to January 4, 2016, will see the $2 increase each way on all standard-sized checked bags. The Florida-based company told FareCompare.com that the reason for the increase is simply because “Christmas and New Year’s is a very high demand period" for the airline.

Currently, Spirit customers pay $30 for a check bag when booking a flight, $35 before online check-in, $40 during online check-in, $50 at the airport, and $100 at the gate. (Related: Know your airline’s carry-on luggage rules before you fly.)

These increased baggage fees land as consumers have an already dim view of the U.S. airline industry, according to our latest survey on airline travel, conducted by the Consumer Reports National Research Center. Read our new report on the best and worst airlines to find out which carrier to fly.