A low base fare can look irresistible, but the cheapest ticket is not always the cheapest trip. The best budget airlines in the USA differ on baggage, seat selection, route coverage, and flexibility. A traveler with one small backpack may save most with an ultra-low-cost carrier, while someone checking a suitcase could get better value from an airline with a higher fare but fewer add-on costs.
For cheap domestic flights, compare the final checkout price rather than the headline fare. In 2026, the main options include Frontier, Spirit, Allegiant, Avelo, Breeze, Sun Country, and Southwest.
How the Main Budget Airlines Compare
Frontier Airlines: Best for very low fares when you pack light
Frontier follows the ultra-low-cost model closely. Every ticket includes one personal item, while carry-on and checked baggage may cost extra unless your fare bundle includes them. The Economy bundle includes a carry-on and standard seat selection, while higher bundles add more benefits.
Baggage prices vary by trip and purchase timing, and airport pricing is generally higher. Frontier’s standard checked-bag limit is also 40 pounds on many bookings, lower than the 50-pound limit common on several competitors, so heavier packers should calculate fees carefully.
Spirit Airlines: Best for choosing between basic and upgraded budget travel
Spirit now offers different travel products instead of only a stripped-down fare. The Value option includes a personal item, with other extras purchased separately. Premium Economy includes a carry-on and a roomier seat, while Spirit First includes a carry-on, first checked bag, Big Front Seat, priority benefits, and other extras.
If you only need a small personal item, the lowest fare may still work well. If you want baggage and more comfort, compare the upgraded Spirit options with traditional airlines before adding extras individually.
Allegiant Air: Best for leisure routes from smaller cities
Allegiant frequently connects smaller or secondary airports with vacation destinations. Every passenger can bring one personal item free, but carry-on and checked bags cost extra. Reserving baggage before arriving at the airport is usually cheaper than paying there.
The network is less useful if you need frequent daily flights or easy connections, but it can be valuable when Allegiant serves your local airport nonstop.
Avelo Airlines: Best for simple point-to-point trips
Avelo focuses on smaller airports and nonstop routes. One personal item is included. Its published 2026 pricing shows carry-on bags from about $39 to $70 and checked bags from about $34 to $70, depending on the trip and when the bag is purchased.
Breeze Airways: Best for underserved city pairs
Breeze also emphasizes point-to-point flying, often linking cities that otherwise require a connection. It serves more than 90 cities across the United States, Mexico, and the Caribbean. Every fare includes a personal item, while a carry-on can be added or is included with Nicer and Nicest bundles.
Breeze can be especially attractive when a nonstop schedule saves several hours. A slightly higher fare may still be the better budget choice if it eliminates a connection, extra airport spending, and a longer travel day.
Sun Country Airlines: Best for travelers flying through Minneapolis
Sun Country is a low-cost carrier with a strong presence at Minneapolis-Saint Paul. Its base approach includes a personal item, while full-size carry-on and checked baggage may cost extra. Bag prices are generally lowest when added early, and the standard checked-bag allowance is up to 50 pounds.
For travelers in its strongest markets, Sun Country can offer competitive leisure fares.
Southwest Airlines: Best for a broader network and free carry-on baggage
Southwest no longer includes two free checked bags for most standard fares. For U.S. mainland travel ticketed or changed on or after April 9, 2026, Basic, Choice, and Choice Preferred fares generally charge $45 for the first checked bag and $55 for the second. Choice Extra includes the first two checked bags, while some loyalty members and eligible cardholders receive bag benefits.
A carry-on plus a personal item remains free, and Southwest has a much broader domestic network than most ultra-low-cost carriers. If you need an overhead-bin bag but will not check luggage, its total price can compete well with airlines that advertise a lower base fare.
Which Airline Is Actually Cheapest for Your Trip?
Use a total-cost test. Imagine a round trip from Baltimore to Orlando. One airline shows a $58 fare each way, but you need a paid carry-on and seat assignment. Another shows $89 each way and includes the carry-on you need. Once extras are added, the second airline may cost less overall.
Before booking, price the same itinerary with the baggage you will actually bring, any seat selection you care about, and the flexibility you need. Saving $30 on airfare can disappear if a farther airport adds $45 in parking, tolls, or rideshare charges.
Useful related topics to explore include cheap flight booking tips, how to avoid airline baggage fees, and the best time to book domestic flights.
What to Check Before Booking
Check personal-item dimensions first because budget carriers can charge for bags that exceed their limits. Buy baggage online early when prices vary by purchase timing. Also look at flight frequency: a carrier with only a few weekly departures may offer a great fare but fewer alternatives after a cancellation.
Finally, compare bundles before buying extras one at a time. Frontier, Spirit, and Breeze offer bundled products that can make sense when you need baggage, seat selection, or flexibility. The cheapest base fare is intentionally minimal, so decide whether minimal actually fits your trip.
Frequently Asked Questions
What is the cheapest budget airline in the USA?
There is no single cheapest airline on every route. Frontier, Spirit, Allegiant, Avelo, and Breeze can all offer very low fares, but the winner changes by route, date, baggage needs, and optional fees. Compare the final checkout price.
Which budget airline is best if I travel with only a personal item?
Ultra-low-cost carriers are often strongest for personal-item-only travelers. Frontier, Spirit, Allegiant, Avelo, and Breeze all include a small under-seat item, subject to each airline’s size limits.
Which airline is best for a free carry-on?
Southwest includes a carry-on and personal item. Spirit Premium Economy and Spirit First include a carry-on, as do certain Frontier and Breeze bundles, so compare bundled fares rather than only the lowest advertised price.
Are budget airlines a good choice for domestic travel?
Yes, especially on nonstop routes. The main trade-off can be schedule depth. Smaller carriers may have fewer replacement flights after disruption, so a slightly higher fare with several daily departures can be worthwhile for time-sensitive trips.
Choosing the Right Budget Airline
The best carrier is the one that stays inexpensive after your real travel needs are added. Pack-light travelers may find Frontier, Spirit, Allegiant, Avelo, or Breeze hard to beat. Sun Country is particularly useful around Minneapolis, while Southwest can deliver stronger value when you want a free carry-on and a larger domestic network. Compare the complete trip cost, not just the first fare you see.