The best budget airlines in the US for 2026

With Spirit gone, the US low-cost map got redrawn. Here are the budget airlines worth knowing in 2026, ranked by all-in cost - not just the teaser base fare - with the honest catch on each, and why no single one is always cheapest.

By the Snagfly team
Updated 5 August 2026 · 6 min read

Key takeaways

No airline is always cheapest. The best value swings by route, date and how you pack - which is why comparing beats loyalty.
Frontier is the closest ultra-low-cost carrier; Southwest often wins on all-in cost thanks to two free bags.
Breeze and Avelo win on point-to-point and small-city routes the big carriers skip.
Watch the total, not the base fare - bags, seats and change fees decide who's actually cheapest.

The budget airlines that matter in 2026

After Spirit's May 2026 shutdown, the low-cost field is smaller but still competitive. Ranked by how often they deliver the cheapest all-in fare:

1. Frontier - the closest thing to Spirit

Frontier carries the ultra-low-cost torch: very low base fares, everything unbundled (bags, seats, carry-ons all cost extra), and a wide US network. Best for: the cheapest possible fare when you can travel light and flexibly. The catch: the add-ons stack up fast, so the teaser price is rarely what you pay.

2. Southwest - cheapest all-in, often

Southwest's base fare isn't rock-bottom, but two free checked bags and no change fees mean the total is frequently the lowest, especially if you check luggage. Best for: travelers who want simple, all-in value. The catch: a mostly point-to-point network and no traditional first class.

3. Breeze Airways - the underserved-route specialist

Breeze focuses on point-to-point routes the big carriers ignore, often nonstop where you'd otherwise connect. Best for: mid-size cities and avoiding a layover. The catch: limited frequencies and a smaller network.

4. Avelo - small-city leisure

Avelo connects smaller airports to leisure destinations, sometimes as the only low-cost option on a route. Best for: flying from a secondary airport near you. The catch: few flights per week and a narrow map.

5. Allegiant - vacation routes, a few days a week

Allegiant links smaller cities to warm-weather and vacation destinations. Best for: occasional leisure trips from a regional airport. The catch: infrequent schedules and heavy add-on fees.

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Read the total, not the teaser

Budget airlines advertise a base fare and make their money on extras - checked bags, carry-ons, seat selection, priority boarding, change fees. A $39 Frontier fare can land above a $79 Southwest fare once you add a bag and a seat. Always compare the all-in cost for how you actually travel - same bags, same seat needs - across carriers before booking.

Why no airline is always cheapest

The cheapest budget airline on your route this month may not be next month - schedules shift, sales rotate, and (as Spirit showed) carriers can leave the market entirely. Loyalty to one budget brand is a weak strategy. The reliable move is to watch your specific route across all of them and book whichever is genuinely lowest when it drops. Pin your destinations and Snagfly does that watching for you, alerting only when a fare falls at least 50% below its verified 90-day median - across every airline that flies the route.

FAQ

What is the cheapest airline in the US in 2026?

There isn't a single cheapest airline - it changes by route, date and how you pack. Frontier usually has the lowest base fares, but Southwest often wins on all-in cost thanks to two free checked bags, and Breeze or Avelo can be cheapest on routes the big carriers skip. Compare the total for your specific trip.

What are the best budget airlines after Spirit shut down?

Frontier is the closest ultra-low-cost replacement, Southwest often has the lowest all-in cost, and Breeze, Avelo and Allegiant cover point-to-point, small-city and leisure routes. On competitive routes, legacy basic-economy fares can also be cheapest.

Is Frontier or Southwest cheaper?

It depends on how you travel. Frontier's base fare is usually lower, but once you add bags and a seat it can cost more than Southwest, which includes two free checked bags and no change fees. Price the all-in total for your trip on both before booking.

How do I always find the cheapest budget flight?

Compare the all-in cost across every budget airline for your route, and track it over time rather than booking the first fare you see. A wishlist alert like Snagfly watches your route across airlines and only pings you when a fare drops at least 50% below its verified baseline.

Keep reading

Spirit Airlines shut down: alternatives

Where Spirit flyers should look now.

Best time to book flights in 2026

What the booking-window data actually says.

Are flight deal alerts worth it?

The honest case for letting deals find you.

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About this guide: Snagfly publishes this page and is one of the services discussed. Airline details, routes and pricing change frequently and are based on publicly available information as of August 2026; check each airline's site before booking. This page describes differences in product model, not a judgement of quality. All third-party names and trademarks belong to their respective owners; this page is not affiliated with or endorsed by any of them.