You found a great airfare. You smiled, clicked, and felt genuinely clever. Then came the seat selection screen. Then the baggage prompt. Then the boarding upgrade nudge. By the time you hit “confirm,” the total had doubled. Sound familiar? This is the modern airline experience for millions of travelers every year, and it’s not an accident.
Global ancillary revenue hit $148.4 billion in 2024, a figure that represents a dramatic leap from the industry’s previous records. Behind every cheap-looking fare is a carefully engineered machine designed to extract more money from you at every step. Let’s look at which airlines are the worst offenders, what their fees actually cost, and why you should read the fine print before you ever touch that “book now” button. Let’s dive in.
1. Spirit Airlines – The Fee Machine That Broke Records
Let’s be real: Spirit Airlines has essentially built its entire brand identity around a low-fare illusion. Spirit followed Frontier at nearly 59 percent ancillary revenue in 2024, making it the second-most dependent airline on fees rather than fares in the country. The price you pay for the ticket includes only the flight itself. Everything else, bags, seat selection, meals, early boarding, printing your boarding pass at the airport, costs extra.
Spirit has again tweaked its pricing structure with a notable hike in checked baggage fees. Passengers opting to pay for their bags at the airport check-in desk now face a charge of $89. That’s not a typo. And the carry-on situation is arguably worse: Spirit’s cheapest fares don’t even allow carry-ons at all, just one personal item that fits under the seat.
Spirit Airlines pads its low base fares so much that compliant customers end up paying an average of 736 percent over the original quote, qualifying Spirit as far and away the worst airline on the planet for extra fees, according to an analysis by NetVoucherCodes. That is a jaw-dropping figure, and it tells the whole story.
2. Frontier Airlines – Paying Agents to Catch You
Frontier’s business model is almost poetic in its brazenness. Frontier claimed the top spot at 62 percent ancillary revenue, breaking the 60 percent threshold in 2024 for the first time. More than half of what the airline earns comes not from selling flights, but from charging you for the things you assumed were part of the flight.
A Senate investigation found that Frontier and Spirit shelled out $26 million in incentives to gate agents in 2022 and 2023 to catch passengers not following airline bag policies, often forcing those passengers to pay a bag fee or miss their flight. Honestly, that detail alone should make anyone pause before booking. Frontier personnel can earn as much as $10 for each bag a passenger is forced to check at the gate.
Frontier sets its maximum bag weight at 40 pounds, a limit that is easy to exceed when packing even a standard-sized suitcase with a reasonable amount in it. Frontier Airlines fees added 376 percent on top of the base fare in the same fee analysis. The numbers speak for themselves.
3. JetBlue Airways – Surge Pricing Comes to Your Suitcase
JetBlue was once considered the “friendly” option between legacy carriers and ultra-low-cost airlines. Those days are gone. JetBlue introduced surge pricing for baggage in 2024, meaning bags cost more on high-demand days. That’s a concept borrowed from ride-sharing apps and applied directly to your suitcase.
JetBlue can actually be worse than standard data shows. If you wait to check your bags at the airport, you’ll pay $10 more per bag, making it $50 for the first bag and $70 for the second. JetBlue was by far the most expensive carrier for seat selection fees among the major full-service airlines analyzed in 2026.
Seat selection fees on JetBlue range from $25 to $100 per flight segment, with extra legroom seats costing up to $319. Think about that for a family of four on a round trip. The math is brutal, and the fees accumulate faster than you’d expect.
4. United Airlines – Hidden Until You’re Already Deep In
United Airlines has become notorious not just for what it charges, but for how hard it makes it to find out. Unless you’re a United Airlines regular, you won’t know what the bag fees are before choosing your flights. The fare prices don’t hint that there might be other charges at all. That’s not an oversight. That’s a strategy.
According to the Senate Permanent Subcommittee on Investigations, United Airlines charged as much as $319 for an extra legroom seat in 2023, the highest of all five airlines examined in the probe. If you prefer to book by phone, expect to pay up to $25 per ticket with United, a fee that competitors like Delta have eliminated.
When it comes to basic economy fares, United is the only one of the major U.S. airlines that doesn’t allow a free carry-on bag. United also charges an additional $25 gate handling fee on top of the regular baggage fee if an economy passenger brings a full-size bag to the gate. That one detail has surprised travelers at the gate more times than anyone can count.
5. American Airlines – The Billion-Dollar Bag King
Here’s the thing: American Airlines might not look like the worst offender at first glance. Its fee structure feels almost normal compared to Spirit or Frontier. But the total revenue picture is staggering. American Airlines brought in $1.24 billion in baggage fees, the highest among all 11 U.S. carriers who reported to the Bureau of Transportation Statistics.
The fees added by American Airlines represent 122 percent on top of the base flight cost, according to the NetVoucherCodes analysis. American charges up to $160 for extra legroom internationally. For a carrier that markets itself as a full-service airline, that is quite the premium on simply stretching your legs on a long flight.
A Senate investigation found that in 2023 alone, American, Delta, United, Frontier, and Spirit collected more than $3 billion in seat fees – not airfare, just fees for booking a specific seat in advance or selecting a slightly better seat. American was a significant contributor to that figure. The scale of it is hard to wrap your head around.
6. Delta Air Lines – Billions From Fees, Not Just Flying
Delta has a reputation as one of the more premium domestic carriers. Its lounges are nicer, its reliability is better, and its loyalty program is arguably the most lucrative. None of that, however, makes it innocent when it comes to fees. Delta Air Lines fees added 158 percent to the base flight cost, according to research by NetVoucherCodes.
The Senate Permanent Subcommittee on Investigations found that Delta Air Lines charged as much as $264 for an extra legroom seat in 2023. Airlines collectively collected over $5 billion in baggage fees and another $4.2 billion from seat selection in a single year. Delta’s piece of that pie is considerable.
I think what frustrates most Delta passengers isn’t the fees themselves, but the way the airline’s premium branding makes them feel unexpected. Delta made $7 billion from its American Express partnership in 2024, more than from actually flying planes profitably. That says everything about where the money actually comes from.
7. Southwest Airlines – The Last Honest Holdout That Just Gave In
For decades, Southwest was the airline that travelers pointed to as proof that a fair, fee-free model could work. It was the one airline that felt like it was actually on your side. That era is officially over. In May 2025, Southwest abandoned its 50-year “bags fly free” policy. The last holdout fell, and with it, the last shred of nostalgia for honest airline pricing.
Starting in May 2025, Southwest discontinued its two free checked bag policy. The airline now charges $35 for the first checked bag, $45 for the second, and $150 for subsequent bags. Southwest launched assigned seating on January 27, 2026, expecting to make $1.5 billion annually from seat selection fees alone.
Southwest used to dominate the value-for-money category, but its new policy of charging for bags and seat selection puts it toward the bottom of the pack. Passengers who built years of brand loyalty around the free-bag promise received nothing in return when it disappeared. That stings.
8. Sun Country Airlines – The Quiet Fee Collector
Sun Country doesn’t get nearly as much attention as Spirit or Frontier when people talk about fee-heavy airlines, but it absolutely deserves a spot on this list. Sun Country Airlines’ fees added 201 percent on top of the base fare in the NetVoucherCodes analysis, putting it firmly among the worst offenders in the domestic market. That’s more than doubling the cost of your ticket through add-ons alone.
The biggest jump in baggage fee revenue among carriers was Sun Country, moving from 3.7 percent to 7.2 percent within a single year. That kind of growth doesn’t happen by accident. It happens when an airline decides to quietly expand its fee infrastructure while passengers aren’t paying close enough attention.
Sun Country tends to attract travelers looking for deals on leisure routes, which makes the fee shock even worse. You book what looks like an affordable vacation flight, then discover the fees add up to something that rivals a full-fare ticket on a different carrier. It’s a classic bait-and-switch in slow motion.
9. Alaska Airlines – Quietly Doubling the Bill
Alaska Airlines often earns praise for its customer service and loyalty program, and that reputation is broadly fair. However, the fee picture tells a more complicated story. Alaska Airlines fees added 105 percent to the price of the base flight, effectively doubling the advertised fare once all the extras are factored in. That puts it well into the company of airlines that charge more than they initially let on.
Alaska Airlines raised its baggage fees back in December 2018 with an increase on first bag fees of 20 percent and second bag fees of 60 percent, and a variety of other fees rising by more than 30 percent, resulting in 40 percent more baggage fee revenue than in previous quarters. The incremental fee creep has continued since.
Alaska does offer ways to offset some of these costs, like co-branded credit cards and elite status benefits. Airlines recoup costs through fees for extras like baggage, priority boarding, and window seats. That $100 airfare that looks like a deal could actually be more expensive than a $150 ticket on another airline after factoring in fees. Alaska is a prime example of why comparison shopping requires looking beyond the base price.
10. Allegiant Air – The Fee-Per-Everything Model
Allegiant Air flies under the radar in many conversations about airline fees, but it has long operated one of the most aggressively unbundled models in the industry. Allegiant Air’s fees added 107 percent to the base fare in the same study that ranked all major U.S. carriers, essentially doubling the cost of every ticket before you even add a bag or choose a seat.
Online travel agencies and search engines incentivize airlines to keep their base ticket prices low so they appear higher in search results. Airlines then recoup costs through fees for extras like baggage, priority boarding, and window seats. Allegiant has mastered this game, typically serving leisure routes where passengers are less likely to be frequent flyers with elite status to protect them.
U.S.-based airlines charge an average of $78.04 per ticket in added fees, but with Allegiant, the gap between the advertised fare and the real total can be particularly jarring. The airline’s routes often look like the cheapest option on search engines, and that’s exactly the point. By the time you’ve added a carry-on, a seat, and priority boarding, the “deal” has vanished entirely.
The Bigger Picture: A System Built on Confusion
Air travel costs come in two parts: the base ticket price, and the many fees that airlines add on during the booking or check-in process. These days, some airline fees can cost more than the fare itself. That’s not an exaggeration. It’s a documented reality backed by Senate investigations, Department of Transportation rulemakings, and years of consumer complaints.
Seat fees increased by 50 percent from 2018 to 2023. Overall, five U.S. carriers collected $12.4 billion in seat fees between 2018 and 2023, in addition to baggage and other charges. In 2024, the Department of Transportation introduced new airline fee regulations that require airlines to disclose baggage fees upfront, provide automatic refunds for cancelled flights, and implement family seating requirements without extra charges. However, the courts put that rule on hold after airlines sued to stop upfront fee disclosure.
Frontier, Spirit, and United appear to avoid the federally mandated transportation excise tax by labeling portions of their charges as non-taxable fees, which creates different tax rates for similar services across airlines. That’s a layer of the fee problem most passengers don’t even know exists. The system is far more complicated, and far more calculated, than it appears on the surface.
The next time a fare looks suspiciously cheap, it probably is. Factor in a carry-on, a seat, and a checked bag, and you might find a “full-service” carrier was the better deal all along. What would you have guessed was the worst airline for hidden fees? Tell us in the comments.
<p>The post Don’t Book That Flight Yet: 10 Airlines With the Worst Hidden Fees first appeared on Travelbinger.</p>