Frontier vs Spirit: both are ultra-low-cost carriers (ULCCs) that advertise fares well below mainstream airlines — but bag fees, seat-selection charges, and poor reliability can quickly erase the savings. The right choice depends on your route, how much you pack, and your tolerance for delays.
Quick Comparison: Frontier vs Spirit 2026
| Feature | Frontier | Spirit |
|---|---|---|
| Base fare range | $19–$199 | $19–$199 |
| Personal item (under seat) | Free | Free |
| Carry-on bag fee | $35–$79 | $49–$89 at gate |
| Checked bag fee (1st bag) | $35–$65 | $39–$69 |
| Seat selection fee | $6–$55 | $5–$50 |
| On-time rate (2025 DOT) | ~70% | ~68% |
| Loyalty program | Frontier Miles | Free Spirit |
| Hub airports | Denver (DEN) | Fort Lauderdale (FLL), Orlando (MCO) |
Base Fares: How Low Do They Actually Go?
Both airlines regularly advertise fares of $19–$49 on competitive routes. These prices are real — but they require:
- Booking 6–8 weeks in advance
- Flying on Tuesday or Wednesday
- Selecting no extras (no seat, no bag, no snacks)
A realistic all-in fare with one carry-on and a selected seat on either airline typically lands at $120–$200 for a domestic one-way — still cheaper than most major carriers, but not dramatically so.
Example: A one-way flight from Las Vegas to Chicago booked 6 weeks out:
- Frontier base fare: $59 + $45 carry-on + $15 seat = $119 total
- Spirit base fare: $55 + $55 carry-on + $12 seat = $122 total
- Southwest (with one free bag included): ~$149 all-in
The gap shrinks fast once you add bags.
Bag Fees: The Biggest Hidden Cost
Bag fees are where both airlines make most of their profit — and where travelers get burned most often.
Frontier bag fees (2026):
- Personal item (fits under seat, ≤18"×14"×8"): Free
- Carry-on (overhead bin): $35 online, up to $79 at the gate
- First checked bag: $35–$65 (route-dependent)
Spirit bag fees (2026):
- Personal item (fits under seat, ≤18"×14"×8"): Free
- Carry-on (overhead bin): $49 online, up to $89 at the gate
- First checked bag: $39–$69
Key rule for both: Never pay bag fees at the gate. Paying online during booking is 30–50% cheaper. Spirit has slightly higher carry-on fees than Frontier, giving Frontier a small edge for carry-on travelers.
Seat Comfort and Cabin Experience
Neither airline offers reclining seats. Both use high-density cabin configurations with 28–30 inch seat pitch — roughly 2 inches less than economy on United or Delta.
Spirit’s Big Front Seat: Located in rows 1–5, this seat offers 36-inch pitch and 18.5-inch width — similar to domestic first class. Prices range from $25 to $100+ depending on route and timing. It’s Spirit’s best feature for travelers willing to pay.
Frontier’s UpFront Plus: Similar premium row seats near the front of the cabin, priced at $30–$80. Worth it on flights over 2 hours if availability is good.
For flights under 90 minutes, the difference in seat quality is minor. For longer flights (3+ hours), consider the upgrade or compare against Southwest’s open seating.
On-Time Performance and Reliability
This is where both airlines fall short. According to 2025 DOT data:
| Airline | On-Time Arrival Rate |
|---|---|
| Delta | ~84% |
| United | ~80% |
| American | ~78% |
| Southwest | ~76% |
| Frontier | ~70% |
| Spirit | ~68% |
Both carriers operate lean fleets with minimal buffer — a single mechanical delay can cascade through the day. If you have a critical connection or time-sensitive trip, the savings may not be worth the risk.
Loyalty Programs
Frontier Miles is a free program where you earn miles per dollar spent (not per mile flown). Elite status tiers offer bonus miles and occasional complimentary bags. It’s a functional program for frequent Frontier flyers.
Free Spirit was restructured following Spirit’s Chapter 11 bankruptcy filing in late 2024. The program still exists, but its long-term value is uncertain. Points and status earned before the restructuring may have reduced value. If you fly Spirit occasionally, join the program — but don’t build a travel strategy around it.
When to Choose Frontier
- You’re flying into or out of Denver (Frontier’s main hub)
- You travel with only a personal item (backpack-sized)
- You’re flexible on travel dates and can book 6+ weeks ahead
- Your route is a Frontier stronghold with multiple daily flights
When to Choose Spirit
- You’re flying out of Fort Lauderdale, Orlando, or Atlanta
- You want the Big Front Seat upgrade on a short domestic flight
- You can score a bundle deal (Spirit Saver$ Club membership can cut prices significantly for frequent flyers)
- Your destination is a leisure market where Spirit has strong frequency
The Bottom Line
For most travelers, Frontier has a slight edge thanks to lower carry-on bag fees and a more stable airline post-2024. Spirit’s bankruptcy restructuring introduced uncertainty about the airline’s future routes and reliability.
Both carriers are worth considering for trips under 3 hours where you pack light. Add bags, select seats, or fly a 4-hour route and the savings evaporate — making Southwest or a sale fare on a major carrier a better deal.
Compare all-in prices with one carry-on before booking. The advertised base fare is rarely the final price.
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