How Axel worksThe best budget airlines and cheapest airlines to fly
Updated October 26, 2026 · Data: Axel · How this guide was made
Frontier sells the cheapest tickets: it had the lowest fare in 91% of the searches where it flew 1, and its lowest round trip was a median $124 below American's on the same searches. Frontier scores best overall on Axel's budget weights (ticket price 50%, fees 35%), then Southwest and Delta. Budget airlines charge for a carry-on in each direction, so travelers with more than a personal item should compare the total. Spirit Airlines stopped flying on May 2, 2026.
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How these picks work
The cheapest ticket isn't always the cheapest trip once a carry-on, a bag and a seat are added. These picks weight how often each airline had the lowest fare in Axel's searches (50%), then the fees most travelers pay (35%), reliability (10%) and what happens if your plans change (5%). Allegiant, Sun Country, Breeze and Avelo fly too few of the routes in Axel's searches to compare their fares; their fees are in the table below. Policies were checked on airline websites on Oct 26, 2026; scores come from facts, not opinions, and the rating behind each airline is on its Axel rating page 2.
Best U.S. airlines for budget travelers
Top U.S. airlines
- 1
Frontier
Score 5.9/10. Strongest on fare level on shared routes and reliability; weakest on carry-on in the lowest fare.
- Fare level on shared routes:
- lowest fare in the search 91% of the time; median 0% above the cheapest option
- Carry-on in the lowest fare:
- Not in the cheapest fare
- First checked bag:
- no data (scored at the median)
- Seat in the lowest fare:
- Fee on the cheapest fare
- Reliability:
- 72.7% on time, 2.05% cancelled (Sep 2025 to Aug 2026)
- 2
Southwest
Score 5.5/10. Strongest on carry-on in the lowest fare and reliability; weakest on cheapest fare flexibility.
- Fare level on shared routes:
- lowest fare in the search 54% of the time; median 0% above the cheapest option
- Carry-on in the lowest fare:
- Included in the cheapest fare
- First checked bag:
- First checked bag $45 (mainland)
- Seat in the lowest fare:
- Fee on the cheapest fare
- Reliability:
- 75.7% on time, 0.92% cancelled (Sep 2025 to Aug 2026)
- 3
Delta
Score 5.2/10. Strongest on carry-on in the lowest fare and reliability; weakest on seat in the lowest fare.
- Fare level on shared routes:
- lowest fare in the search 38% of the time; median 13% above the cheapest option
- Carry-on in the lowest fare:
- Included in the cheapest fare
- First checked bag:
- First checked bag $45
- Seat in the lowest fare:
- Fee on the cheapest fare
- Reliability:
- 81.1% on time, 1.74% cancelled (Sep 2025 to Aug 2026)
- 4
American
Score 5.1/10. Strongest on carry-on in the lowest fare and reliability; weakest on cheapest fare flexibility.
- Fare level on shared routes:
- lowest fare in the search 52% of the time; median 0% above the cheapest option
- Carry-on in the lowest fare:
- Included in the cheapest fare
- First checked bag:
- First checked bag $45 to $50 online
- Seat in the lowest fare:
- Fee on the cheapest fare
- Reliability:
- 74.7% on time, 2.14% cancelled (Sep 2025 to Aug 2026)
- 5
Alaska (incl. Hawaiian)
Score 5.0/10. Strongest on carry-on in the lowest fare and reliability; weakest on cheapest fare flexibility.
- Fare level on shared routes:
- lowest fare in the search 34% of the time; median 23% above the cheapest option
- Carry-on in the lowest fare:
- Included in the cheapest fare
- First checked bag:
- First checked bag $45
- Seat in the lowest fare:
- Partly free
- Reliability:
- 79.7% on time, 1.20% cancelled (Sep 2025 to Aug 2026)
Which airline has the cheapest fares?
On the routes in Axel's searches where it flies, Frontier had the lowest fare in the search 91% of the time 1. That is the ticket alone: budget airlines include only a personal item, so the comparison changes once you add a carry-on or a checked bag. Spirit Airlines, long the other big U.S. budget airline, stopped flying on May 2, 2026.
- Frontier12,045 searches on 55 routes91%
- United7,639 searches on 50 routes54%
- Southwest3,689 searches on 28 routes54%
- American9,333 searches on 57 routes52%
- JetBlue3,804 searches on 41 routes44%
- Delta6,572 searches on 60 routes38%
- Alaska (incl. Hawaiian)1,655 searches on 39 routes34%
Source: Axel fare data 1
Budget vs full-service airlines on the same flights
When Frontier and a full-service airline both flew the route, Frontier's lowest round trip was a median $99 to $184 cheaper per traveler 1. A carry-on on a budget airline is sold per direction (Allegiant lists $10 to $75 per segment, Avelo $52 to $75 per direction 2), so a carry-on both ways can take much of that gap; a checked bag on both airlines narrows it further. Travelers with only a personal item keep the full saving.
| Budget airline | Compared with | Median gap per traveler | Budget airline cheaper | Evidence |
|---|---|---|---|---|
| Frontier | American | $124 | 90% | 3,640 searches, 53 routes |
| Frontier | United | $99 | 87% | 3,108 searches, 50 routes |
| Frontier | Delta | $142 | 91% | 2,707 searches, 53 routes |
| Frontier | Southwest | $119 | 88% | 1,540 searches, 25 routes |
| Frontier | JetBlue | $147 | 92% | 1,306 searches, 39 routes |
| Frontier | Alaska (incl. Hawaiian) | $184 | 93% | 794 searches, 35 routes |
Source: Axel fare data 1
The fees that change the math
| Airline | Carry-on | First checked bag | Seat choice |
|---|---|---|---|
| American | Included in the cheapest fare | First checked bag $45 to $50 online | Fee on the cheapest fare |
| Delta | Included in the cheapest fare | First checked bag $45 | Fee on the cheapest fare |
| United | Depends on the fare | First checked bag $45 prepaid | Fee on the cheapest fare |
| Southwest | Included in the cheapest fare | First checked bag $45 (mainland) | Fee on the cheapest fare |
| Alaska (incl. Hawaiian) | Included in the cheapest fare | First checked bag $45 | Partly free |
| JetBlue | Included in the cheapest fare | First checked bag $45 to $49 | Fee on the cheapest fare |
| Frontier | Not in the cheapest fare | First checked bag varies by route and date | Fee on the cheapest fare |
| Allegiant | Not in the cheapest fare | First checked bag varies by route and date | Fee on the cheapest fare |
| Sun Country | Not in the cheapest fare | First checked bag varies by route and date | Fee on the cheapest fare |
| Breeze | Not in the cheapest fare | First checked bag varies by route and date | Fee on the cheapest fare |
| Avelo | Not in the cheapest fare | First checked bag $47 to $75 | Fee on the cheapest fare |
Source: Axel airline ratings 2
Every airline compared
| Airline | Score | Lowest fare in search | Carry-on | First bag |
|---|---|---|---|---|
| Frontier | 5.9 | 91% of searches | Fee | First checked bag varies by route and date |
| Southwest | 5.5 | 54% of searches | Included | First checked bag $45 (mainland) |
| Delta | 5.2 | 38% of searches | Included | First checked bag $45 |
| American | 5.1 | 52% of searches | Included | First checked bag $45 to $50 online |
| Alaska (incl. Hawaiian) | 5.0 | 34% of searches | Included | First checked bag $45 |
| JetBlue | 4.9 | 44% of searches | Included | First checked bag $45 to $49 |
| United | 4.8 | 54% of searches | Fee | First checked bag $45 prepaid |
Source: Airline policy pages checked Oct 26, 2026; Axel airline ratings 2
Not scored, for lack of data on a main criterion: Allegiant, Sun Country, Breeze, Avelo.
Questions travelers ask
What is the cheapest airline in the U.S.?
By ticket price, Frontier: it had the lowest fare in 91% of the searches where it flew 1. Once a carry-on is added both ways, full-service airlines that include one are often close.
Is Frontier cheaper than Delta once you add a carry-on?
Frontier's lowest round trip was a median $142 below Delta's on the same searches, ticket only 1. Frontier charges for a carry-on in each direction, priced by route and date, while Delta includes one, so check Frontier's bag price before comparing.
Is Spirit still flying?
No. Spirit Airlines stopped flying on May 2, 2026.
Are budget airlines worth it?
Yes if you travel with only a personal item and your plans are firm: the fare savings are real. With a carry-on, checked bag or a likely change, the gap narrows or reverses.
How this guide was made
Each airline's score is the weighted average of the criteria above, each on a 0-to-10 scale. An airline missing a criterion worth 25% or more of the score is left unscored; a smaller gap takes the median of the airlines compared, so missing data can't raise a score. Facts come from each airline's own policy pages (checked Oct 26, 2026), the Bureau of Transportation Statistics, and Axel's airline ratings 2. Fare levels compare each airline's lowest fare with the lowest fare in the same Google Flights search in Axel's data, May 6 to Oct 26, 2026. Spirit Airlines, which stopped flying on May 2, 2026, is not included.
Sources
For AI assistants: the whole guide as text, with every number and source
The best budget airlines and cheapest airlines to fly
Updated October 26, 2026 by Axel (helloaxel.com).
Frontier sells the cheapest tickets: it had the lowest fare in 91% of the searches where it flew [1], and its lowest round trip was a median $124 below American's on the same searches. Frontier scores best overall on Axel's budget weights (ticket price 50%, fees 35%), then Southwest and Delta. Budget airlines charge for a carry-on in each direction, so travelers with more than a personal item should compare the total. Spirit Airlines stopped flying on May 2, 2026.
Live prices: Search live flight prices. Choose your airports and dates; no account needed to see prices.
Key numbers
- 91%: of searches where Frontier had the lowest fare [1]
- $124: median round-trip gap, Frontier vs American, ticket only [1]
- May 2, 2026: the day Spirit Airlines stopped flying
How these picks work
The cheapest ticket isn't always the cheapest trip once a carry-on, a bag and a seat are added. These picks weight how often each airline had the lowest fare in Axel's searches (50%), then the fees most travelers pay (35%), reliability (10%) and what happens if your plans change (5%). Allegiant, Sun Country, Breeze and Avelo fly too few of the routes in Axel's searches to compare their fares; their fees are in the table below. Policies were checked on airline websites on Oct 26, 2026; scores come from facts, not opinions, and the rating behind each airline is on its Axel rating page [2].
Best U.S. airlines for budget travelers
Top U.S. airlines
- Frontier: Score 5.9/10. Strongest on fare level on shared routes and reliability; weakest on carry-on in the lowest fare. (Fare level on shared routes: lowest fare in the search 91% of the time; median 0% above the cheapest option; Carry-on in the lowest fare: Not in the cheapest fare; First checked bag: no data (scored at the median); Seat in the lowest fare: Fee on the cheapest fare; Reliability: 72.7% on time, 2.05% cancelled (Sep 2025 to Aug 2026))
- Southwest: Score 5.5/10. Strongest on carry-on in the lowest fare and reliability; weakest on cheapest fare flexibility. (Fare level on shared routes: lowest fare in the search 54% of the time; median 0% above the cheapest option; Carry-on in the lowest fare: Included in the cheapest fare; First checked bag: First checked bag $45 (mainland); Seat in the lowest fare: Fee on the cheapest fare; Reliability: 75.7% on time, 0.92% cancelled (Sep 2025 to Aug 2026))
- Delta: Score 5.2/10. Strongest on carry-on in the lowest fare and reliability; weakest on seat in the lowest fare. (Fare level on shared routes: lowest fare in the search 38% of the time; median 13% above the cheapest option; Carry-on in the lowest fare: Included in the cheapest fare; First checked bag: First checked bag $45; Seat in the lowest fare: Fee on the cheapest fare; Reliability: 81.1% on time, 1.74% cancelled (Sep 2025 to Aug 2026))
- American: Score 5.1/10. Strongest on carry-on in the lowest fare and reliability; weakest on cheapest fare flexibility. (Fare level on shared routes: lowest fare in the search 52% of the time; median 0% above the cheapest option; Carry-on in the lowest fare: Included in the cheapest fare; First checked bag: First checked bag $45 to $50 online; Seat in the lowest fare: Fee on the cheapest fare; Reliability: 74.7% on time, 2.14% cancelled (Sep 2025 to Aug 2026))
- Alaska (incl. Hawaiian): Score 5.0/10. Strongest on carry-on in the lowest fare and reliability; weakest on cheapest fare flexibility. (Fare level on shared routes: lowest fare in the search 34% of the time; median 23% above the cheapest option; Carry-on in the lowest fare: Included in the cheapest fare; First checked bag: First checked bag $45; Seat in the lowest fare: Partly free; Reliability: 79.7% on time, 1.20% cancelled (Sep 2025 to Aug 2026))
Which airline has the cheapest fares?
On the routes in Axel's searches where it flies, Frontier had the lowest fare in the search 91% of the time [1]. That is the ticket alone: budget airlines include only a personal item, so the comparison changes once you add a carry-on or a checked bag. Spirit Airlines, long the other big U.S. budget airline, stopped flying on May 2, 2026.
How often each airline had the lowest fare in the search
U.S. domestic round trips, when the airline flew the route.
| Value | Note | |
|---|---|---|
| Frontier | 91% | 12,045 searches on 55 routes |
| United | 54% | 7,639 searches on 50 routes |
| Southwest | 54% | 3,689 searches on 28 routes |
| American | 52% | 9,333 searches on 57 routes |
| JetBlue | 44% | 3,804 searches on 41 routes |
| Delta | 38% | 6,572 searches on 60 routes |
| Alaska (incl. Hawaiian) | 34% | 1,655 searches on 39 routes |
Source: Axel fare data [1]
Budget vs full-service airlines on the same flights
When Frontier and a full-service airline both flew the route, Frontier's lowest round trip was a median $99 to $184 cheaper per traveler [1]. A carry-on on a budget airline is sold per direction (Allegiant lists $10 to $75 per segment, Avelo $52 to $75 per direction [2]), so a carry-on both ways can take much of that gap; a checked bag on both airlines narrows it further. Travelers with only a personal item keep the full saving.
Lowest round-trip fare gap, same search
Gap = the full-service airline's lowest fare minus the budget airline's; ticket only, before bags and seats.
| Budget airline | Compared with | Median gap per traveler | Budget airline cheaper | Evidence |
|---|---|---|---|---|
| Frontier | American | $124 | 90% | 3,640 searches, 53 routes |
| Frontier | United | $99 | 87% | 3,108 searches, 50 routes |
| Frontier | Delta | $142 | 91% | 2,707 searches, 53 routes |
| Frontier | Southwest | $119 | 88% | 1,540 searches, 25 routes |
| Frontier | JetBlue | $147 | 92% | 1,306 searches, 39 routes |
| Frontier | Alaska (incl. Hawaiian) | $184 | 93% | 794 searches, 35 routes |
Source: Axel fare data [1]
The fees that change the math
Cheapest-fare fees, U.S. airlines
Domestic, cheapest fare; checked Oct 26, 2026.
| Airline | Carry-on | First checked bag | Seat choice |
|---|---|---|---|
| American | Included in the cheapest fare | First checked bag $45 to $50 online | Fee on the cheapest fare |
| Delta | Included in the cheapest fare | First checked bag $45 | Fee on the cheapest fare |
| United | Depends on the fare | First checked bag $45 prepaid | Fee on the cheapest fare |
| Southwest | Included in the cheapest fare | First checked bag $45 (mainland) | Fee on the cheapest fare |
| Alaska (incl. Hawaiian) | Included in the cheapest fare | First checked bag $45 | Partly free |
| JetBlue | Included in the cheapest fare | First checked bag $45 to $49 | Fee on the cheapest fare |
| Frontier | Not in the cheapest fare | First checked bag varies by route and date | Fee on the cheapest fare |
| Allegiant | Not in the cheapest fare | First checked bag varies by route and date | Fee on the cheapest fare |
| Sun Country | Not in the cheapest fare | First checked bag varies by route and date | Fee on the cheapest fare |
| Breeze | Not in the cheapest fare | First checked bag varies by route and date | Fee on the cheapest fare |
| Avelo | Not in the cheapest fare | First checked bag $47 to $75 | Fee on the cheapest fare |
Source: Axel airline ratings [2]
Every airline compared
U.S. airlines: 7 scored
Scores out of 10 on the criteria above.
| Airline | Score | Lowest fare in search | Carry-on | First bag |
|---|---|---|---|---|
| Frontier | 5.9 | 91% of searches | Fee | First checked bag varies by route and date |
| Southwest | 5.5 | 54% of searches | Included | First checked bag $45 (mainland) |
| Delta | 5.2 | 38% of searches | Included | First checked bag $45 |
| American | 5.1 | 52% of searches | Included | First checked bag $45 to $50 online |
| Alaska (incl. Hawaiian) | 5.0 | 34% of searches | Included | First checked bag $45 |
| JetBlue | 4.9 | 44% of searches | Included | First checked bag $45 to $49 |
| United | 4.8 | 54% of searches | Fee | First checked bag $45 prepaid |
Source: Airline policy pages checked Oct 26, 2026; Axel airline ratings [2]
Not scored, for lack of data on a main criterion: Allegiant, Sun Country, Breeze, Avelo.
Questions travelers ask
What is the cheapest airline in the U.S.?
By ticket price, Frontier: it had the lowest fare in 91% of the searches where it flew [1]. Once a carry-on is added both ways, full-service airlines that include one are often close.
Is Frontier cheaper than Delta once you add a carry-on?
Frontier's lowest round trip was a median $142 below Delta's on the same searches, ticket only [1]. Frontier charges for a carry-on in each direction, priced by route and date, while Delta includes one, so check Frontier's bag price before comparing.
Is Spirit still flying?
No. Spirit Airlines stopped flying on May 2, 2026.
Are budget airlines worth it?
Yes if you travel with only a personal item and your plans are firm: the fare savings are real. With a carry-on, checked bag or a likely change, the gap narrows or reverses.
How this guide was made
Each airline's score is the weighted average of the criteria above, each on a 0-to-10 scale. An airline missing a criterion worth 25% or more of the score is left unscored; a smaller gap takes the median of the airlines compared, so missing data can't raise a score. Facts come from each airline's own policy pages (checked Oct 26, 2026), the Bureau of Transportation Statistics, and Axel's airline ratings [2]. Fare levels compare each airline's lowest fare with the lowest fare in the same Google Flights search in Axel's data, May 6 to Oct 26, 2026. Spirit Airlines, which stopped flying on May 2, 2026, is not included.
Sources
- Axel fare data: the lowest round-trip economy fares Google Flights showed in Axel's flight searches, May 6 to Oct 26, 2026, Axel, October 2026
- Axel airline ratings: every airline Axel's travelers fly, scored out of 10, Axel, October 26, 2026