Spirit Airlines reveals what you most hate about it Unsurprisingly perhaps, considering Spirit charges its passengers up to $100/£63 to travel with a carry-on bag, it was the target of 40 per cent of the 28,205 rants, while fees was among the five "most hated" aspects of flying. Other airlines to garner the attention of irate fliers were Delta (12 per cent), United (10 per cent), American (eight per cent) and Southwest (7 per cent). Delays, services, lost bags and seats were the other aspects of flying that attracted the most complaints. The word "suck," meanwhile, was used by 914 respondents, while "a***" came up 370 times, "crap" 201 times, the "S-word" 113 times and the "F-bomb" 75 times. "I think if any organisation asks for feedback, you would expect the vast majority of responses would be directed at the company that seeks it," said Ben Baldanza, Spirit's president and CEO. But in this case, we were surprised that most consumers chose to share their frustrations about other airlines. Recent research revealed that Spirit Airlines is more reliant on extras than any other airline in the world. Ancillary sources account for 38.4 per cent of its total revenue. Spirit's "optional" charges include a $26 fee for carry-on bags (this increases to $36 if added to the booking during online check-in, or $100 at the airport gate); $21 to check in a bag (rising to $31-$100); and between $5-$12 for seat selection. It also adds a "passenger usage fee" of $8.99 to $16.99 to all bookings made online. How does Spirit compare with Ryanair for extra fees? Spirit Carry-on bag - from $26/£16.35 (during online booking) to $100/£62.95 (at the gate) Checked bag - from $21/£13.20 (during online booking) to $100 (at the gate) Seat selection - from $1/£0.65 to $50/£31.45 for regular seats or $12/£7.55 to $199/£125.25 for extra legroom Infant fee - free Boarding pass reissue - $10/£6.30 Booking fee - $8.99-$16.99/£5.60-£10.70 Name change fee - $120/£75.55 Ryanair Carry-on bag - no charge Checked bag - from £15 to £40, depending on the size of the bag and the departure date Seat selection - £5 for regular seats, £10 for premium seats Infant fee - £20 Boarding pass reissue - £15 Booking fee - none (though there is a 2% charge for credit card use) Name change fee - £110 (unless spotted within 24 hours of booking)