What is the cheapest airline to fly in the US?

Frontier Airlines has the lowest base fares in the US, regularly offering $19-39 one-way tickets. However, after adding fees for carry-on bags, seat selection, and other extras, Southwest Airlines is often cheaper when comparing total trip cost because it includes two free checked bags and no change fees.

Is Spirit Airlines worth it?

Spirit can be worth it if you're traveling solo with only a personal item (backpack), don't need seat selection, and are prepared for a no-frills experience. But once you add bags and seat fees, the total price often matches or exceeds Southwest or JetBlue, which offer significantly better service.

Which budget airline has the most legroom?

JetBlue offers the most legroom among budget-friendly carriers at 32+ inches in economy. Southwest comes second at about 31-32 inches. Spirit and Frontier have the least legroom at 28 inches of pitch.

Are Avelo and Breeze Airways good airlines?

Both are solid options if they serve your route. Avelo has excellent on-time performance and flies from smaller, easier airports. Breeze connects cities that other airlines skip. Both are newer airlines with smaller fleets, so route options and flight frequency are limited.

Do budget airlines charge for carry-on bags?

Spirit, Frontier, Allegiant, and JetBlue's Blue Basic fare all charge for carry-on bags, typically $35-65 each way. Southwest includes a carry-on for free. A personal item (small backpack that fits under the seat) is free on all US airlines.

Best Budget Airlines in the US

The Best Budget Airlines in the US, Ranked

Budget airlines aren't all the same. Some give you a genuinely good experience at a lower price. Others lure you in with a $39 fare and then charge you $65 for a carry-on bag. Knowing the difference saves you real money and a lot of frustration.

Here's how every budget and low-cost carrier in the US stacks up, from best to worst.

1. Southwest Airlines

Southwest isn't technically an ultra-low-cost carrier, but it consistently delivers the best value in US domestic air travel. Here's why it tops the list.

Two free checked bags per person. No change fees. No cancellation fees. Free same-day standby. That's not marketing spin. That's hundreds of dollars in savings per trip that other airlines treat as profit centers.

The base fare might look $20-40 higher than Spirit or Frontier on the same route. But add in a carry-on bag ($35-65), a checked bag ($30-50), and seat selection ($5-25) on those carriers, and Southwest is almost always cheaper when you compare total cost.

The catch? No assigned seating (though that's changing), a more limited route network than the Big Three, and no international flights beyond Mexico and the Caribbean.

2. JetBlue

JetBlue bridges the gap between budget and full-service better than any US airline. Even in their cheapest Blue Basic fare, you get free snacks, free drinks, free WiFi, and seatback entertainment with live TV.

JetBlue also offers the most legroom in economy at 32+ inches, which is a full 2 inches more than most competitors. Their Blue fare includes a free carry-on and personal item. Only Blue Basic charges for a carry-on.

The airline's biggest limitation is its route network. JetBlue focuses on the East Coast, Florida, the Caribbean, and select West Coast cities. If you're flying from a JetBlue city, it's hard to beat the value.

3. Avelo Airlines

Avelo is the newcomer worth watching. Launched in 2021, this airline focuses on underserved routes from smaller airports, which means less competition and often lower fares. They fly from Burbank, New Haven, and several other secondary airports that are easier to get through than major hubs.

Avelo earned impressive marks for on-time performance, ranking second among all US airlines for full-year on-time arrivals. Fares start low, and while bags aren't free, the fees are reasonable compared to Spirit or Frontier.

4. Breeze Airways

Breeze is another newer airline with a clever strategy: connecting smaller cities that other airlines don't serve nonstop. Founded by the same person who started JetBlue, Breeze focuses on routes like Charleston to San Francisco or New Orleans to Hartford.

Their "Nice" fare includes a personal item only, while "Nicer" adds a carry-on and checked bag. Prices are competitive, and the experience is generally pleasant. The fleet is newer, which means more comfortable seats and better technology.

The downside is a limited route network and fewer daily frequencies, which makes rebooking tough during disruptions.

5. Frontier Airlines

Frontier has the cheapest base fares in the US. Period. You can regularly find $19-39 one-way fares on their routes. But the total cost is where things get tricky.

A carry-on bag costs $35-65 depending on when you add it. Seat selection is $5-25. Want to sit with your travel partner? That's extra. Want a bottle of water? That's $3. These fees add up fast, and many travelers end up paying more than they would have on Southwest or JetBlue.

Frontier also has the worst on-time performance and highest cancellation rate among major US airlines, which means a higher chance of disruption on any given trip.

The strategy: Frontier works if you're traveling solo with just a backpack (personal item is free), you don't care about seat selection, and you're flexible enough to handle delays.

6. Spirit Airlines

Spirit is in a similar camp as Frontier with ultra-low base fares and fees for everything else. The seats are the tightest in the industry at 28 inches of pitch with minimal padding. There's no free entertainment, no free snacks, and no free drinks beyond water.

Spirit's Big Front Seat is a bright spot. It's essentially a domestic first-class-width seat at a fraction of the price. If you can snag one for $30-50 extra, it transforms the experience.

Spirit's complaint ratio is the second-highest among major US airlines, and customer service during disruptions is notoriously poor. Know what you're getting into.

7. Allegiant Air

Allegiant specializes in connecting small and mid-size cities to vacation destinations like Las Vegas, Orlando, and Florida beaches. If your local airport has Allegiant service, it might be the only nonstop option to your destination.

The fees are similar to Spirit and Frontier. The aircraft are older, which means less comfortable seats. Flight frequency is low, often just a few times per week, which makes schedule flexibility nearly impossible.

Allegiant works best for leisure travelers who are flexible on dates and flying from a smaller city.

How to Actually Save Money on Budget Airlines

Compare total cost, not base fare. Add bags, seat selection, and any extras before comparing prices. Use Google Flights, which shows the base fare plus common fees.
Pack light. If you can fit everything in a personal item (backpack under the seat), you'll avoid the biggest fee on ultra-low-cost carriers.
Book bags at time of purchase. Bag fees increase the closer you get to departure. Adding a bag at the airport gate can cost 2-3 times the online price.
Consider airline credit cards. Frontier and Spirit both offer cards that include free bags. If you fly them regularly, the annual fee pays for itself quickly.
Check Southwest last. After pricing out the budget carriers with all fees included, compare to Southwest's all-in price. You'll be surprised how often Southwest wins.

The Bottom Line

Southwest and JetBlue offer the best overall value among US budget carriers because they include more in the base fare. Frontier and Spirit can save you money if you're a minimalist traveler with a backpack and zero expectations. Avelo and Breeze are worth checking if they serve your route. Always compare total cost, never base fare.