Between the cramped seats and unappetizing food most travelers are doomed to in economy class, plane travel can already be pretty unpleasant. That unpleasantness is only compounded by the airline fees that keep climbing year after year, adding unexpected expenses on top of already pricey tickets. Sadly, that goes even for low-cost favorites like JetBlue, who've just announced checked bag fees starting this year.

To help you navigate the complex tangle of costs that now go hand-in-hand with air travel, check out this list of the 10 worst airline fees.

10. Non-Internet Booking Fees

Although it makes sense to charge for changing or canceling tickets, the fees actually start right at the initial booking phase. Most airlines charge extra to customers who prefer to book over the phone or in person rather than online. Charges for the vast majority of major airlines (American, Delta, JetBlue, United, US Airways, etc.) are $25 for phone bookings and $35 for in-person bookings, but Allegiant deserves a special mention for charging $10 per segment for all methods -- on top of a $15 "convenience" fee.

9. Overweight Baggage Fees

What airlines consider overweight or oversize baggage varies greatly with each company, which makes it increasingly important to pore over online FAQs before even starting to pack. US-American, United and Delta lead the way by charging a whopping $100 for bags between 50 and 70 pounds and $200 for 71 to 100 pounds, along with a $200 fee for bags larger than 62 inches. Allegiant and Spirit are also noteworthy for considering bags over just 41 pounds to be overweight, although their fees are also smaller, coming in at $50-75 and $25-100 respectively. All fliers would be wise to weigh their bags before departure.

8. Carry-on Bag Fees

Most airlines don't charge for carry-on bags (yet) except for three: Allegiant, Frontier, and Spirit. Frontier's fees aren't too bad at $25-50, depending on booking method. Allegiant isn't too far behind at $10-35 online and $35-75 elsewhere. But it's Spirit that stands out (of course) with fees up to $100 for one carry-on bag for non-members. We'd tell you to check your bag instead, but even that can cost up to $100. Yikes!

7. Unaccompanied-Minor Fees

Having a young child escorted through the airport and seated near the cabin crew is certainly a good idea for the parents' peace of mind, but it comes at a hefty price of $75-125 for most airlines. Southwest's unaccompanied minor fees are set at a reasonable $50, but if the child is flying American, United, or US Airways, get ready to shell out an additional $150. And that goes double for round trips, of course ... and some airlines don't allow unattended minors at all. Do your research before booking!

6. Seat Selection Fees

Seat selection is an increasingly popular way to nickel and dime passengers by letting them pay a premium for more comfortable seats. These upgraded seats are often located in exit rows or near the bulkhead, which offer more legroom or storage space. Passengers can pay anywhere from $4 to $100 for the luxury of a preferred seat, depending on the airline. But beware: The extra legroom sometimes comes at the cost of seat width, seatback entertainment, the ability to recline, or even warmth in the case of exit row seats.

5. Pet Fees

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Most pet owners would feel safer with their pooch or kitty sitting with them in the cabin rather than in the dark, cold cargo section reserved for pets. Air Canada charges only $50 for the privilege, but most others will tack on a $100-125 fee to your ticket. Delta's fee is particularly high at $200, and Hawaiian tops the list with a fee of $225 for having your pet in the cabin during one of their longer flights to or from the continental US. Some airlines don't allow pets in the cabin, so once again, do your research before booking.

4. Ticket Change Fees

Sometimes changing the day of your flight or canceling it altogether is simply unavoidable, but keep in mind that some serious charges may apply, depending on the airline and the change or cancellation date. Many airlines charge a reasonable $25-75 for same-day changes, but any other changes and cancellations may incur some serious fees, particularly when it comes to Delta (up to $450), US Airways (up to $750), and United (up to $1,000, which could book a whole new flight or five!).

3. WiFi Fees

Let's face it, most airplanes' in-flight entertainment systems are mediocre enough to make your miss your phone's Internet connectivity dearly, especially on long transoceanic flights. If you absolutely need WiFi onboard to get some work done or entertain yourself, you'll have to factor it into your ticket price: Airlines charge up to $19.95 for mobile devices and up to $49.00 for computers per leg of your trip, except low-cost carrier JetBlue, whose basic FlyFi service is free ... or at least free for the moment, while it's still in beta.

2. Snacks and Drinks

Complimentary snacks and drinks used to be a no-brainer on just about any flight, regardless of length, but nowadays you're increasingly likely to be paying for every pretzel you eat. Most airlines except Spirit and Allegiant still offer water and soft drinks for free, but the same can't be said for food. You can expect to pay anywhere from $1 to $12 for snacks, unless you're flying with AirTran, Delta, JetBlue, Southwest or United, who all still offer complimentary snacks.

1. Checked Bag Fees

With airlines constantly trying to turn profits, even one checked bag is enough to incur a fee in the vast majority of cases. The standard fee found on most airlines is $25, but some, including Frontier, Hawaiian, and Spirit, charge more or less depending on frequent-flyer membership and booking method. Be careful with Spirit in particular: If you don't book your flight online, you'll pay up to $100 for your first checked bag. Southwest, meanwhile, bucks the trend by not charging anything for checked bags (or carry-on bags, for that matter). And JetBlue, long the industry favorite for its free-checked-bag policy, is going the way of the older airlines this year, with plenty of new checked-bag fees to annoy fliers. Adieu, JetBlue.

Liked this article? Read The World's 10 Most Expensive Plane Tickets and 10 Places You Should Go While the Dollar Is Strong . Also check out Hopper's Airline Fees Calculator to find out how much your flight really costs.

This article originally appeared on Hopper.com .