An anonymous contributor submitted this Argyle Sweater, commenting that “adding a Spirit sign would have made this funny. Without that, I’m just lost“, which was a comment that I didn’t understand.
For those who might not be able to intuit the Spanish, she’s saying “But, I am Dora“. Even without that, I thought the point of the joke was fairly clear, since many airlines now charge for all sorts of services that used to be automatic and complimentary. However, it turned out that Spirit Airlines (a no frills company with which I have never had the misfortune to fly) was the first airline to charge for carry-on baggage, even though there now are other companies that have adopted same the odious practice.
P.S. The Argyle Sweater really should get a prize for the MoSt AnNoYiNg FoNt in use by any newspaper comic.
Comics I Don't Understand 
Spirit Airlines is notorious for including almost none of the traditional stuff with a ticket. The joke is that on sitting down in the plane you’re given the option for pressurized air for an additional fee.
Additionally, Dora the Explorer’s sentient backpack is her well-known companion in the original and best known incarnation of her television show. Granted, so are her sentient map (who sits in a pocket on the side of Backpack that should be visible at this angle) and Boots the Monkey who aren’t present.
Spirit has not lost the reputation:
It seems fair for the airline to charge a fee for her sentient backpack. After all, every other sentient being who wants to fly has to pay for a ticket.
It does not take up an extra seat and does not eat.