Flights St Louis → Phoenix
As of November 2026, economy flights from St Louis to Phoenix have a typical range USD 397–800, median USD 561. Full range across all 205 offers: USD 340–884. We found 22% of 205 offers from budget carriers (around USD 528) and 78% from full-service carriers (around USD 561).
Preview snapshot — prices change. Search for live results.
Data collected by LetsFG's multi-source price checks — every airline and the major booking sites checked for this route. How we collect data →
Best offers by airline: St Louis → Phoenix
Based on 205 offers · November 2026. Prices and availability change — run a live search to confirm.
Bag & seat fees: St Louis → Phoenix
Add-on pricing from the cheapest available offer per airline · November 2026 · USD
| Airline | Carry-on | Checked bag | Seat selection |
|---|---|---|---|
| Frontier Airlines | USD 164 | USD 166 | — |
| United Airlines | Included | USD 35 | — |
| American Airlines | Included | USD 35 | — |
| American | — | USD 110 | — |
| Southwest Airlines | Included | Included | — |
| Delta | Included | USD 35 | — |
| Alaska Airlines | Included | — | — |
Fees are estimates from the prices we checked and may not reflect your specific itinerary, booking class, or payment method. Run a live search for exact pricing.
How much do flights from St Louis to Phoenix cost?
Based on 205 offers · November 2026
St Louis to Phoenix flights ranged from USD 340 to USD 884 across 205 offers analyzed in November 2026. Two fare clusters detected: budget fares around 585 and premium fares around 802 The chart below shows how prices distributed across all 205 offers.
These 205 offers (November 2026) span multiple departure dates and booking windows — your travel dates may fall anywhere in this distribution. Only a live search shows where your specific trip lands.
50% of offers priced between USD 499 and USD 578
What hidden fees do St Louis to Phoenix flights charge?
Ancillary fees — bags, seat selection, and payment surcharges — can add 10–25% to the base fare on St Louis to Phoenix routes. The breakdown below is based on 205 offers analyzed in November 2026.
| Carrier | Avg fee (USD) | % of base fare |
|---|---|---|
| F9 | 116 | 25% |
| UA | 45 | 8% |
| AA | 116 | 26% |
| American | 110 | 28% |
| WN | 20 | 3% |
| DL | 45 | 7% |
| AS | 10 | 1% |
Frontier Airlines: base ~USD 412 + fees USD 116 = ~USD 528 total. Alaska Airlines: base ~USD 809 + fees USD 10 = ~USD 819 total.
Frontier Airlines's USD 116 ancillary fees narrow the gap with Alaska Airlines's lower-fee model — the USD 397 base difference shrinks to USD 291 after fees. Always compare total cost, not just the advertised base fare.
Estimates based on median total minus average ancillary fee. Actual base fares vary by itinerary.Fee levels vary significantly across carriers on this route — some carriers charge 50%+ above the base fare in ancillary fees.
Run your search to see itemized fees for your itineraryWhich airline is cheapest from St Louis to Phoenix?
8 airlines flew St Louis to Phoenix in this dataset. The route shows a clear split between low-cost and full-service carriers. Knowing the airline isn't enough — the typical fare range below shows how far prices swing on each one. Median and range include all fees we recorded.
Even on the cheapest airline (Frontier), fares ranged USD 342–358 in this snapshot. Your exact price depends on your dates and how far ahead you book — run a live search to see your number →
| Airline | Offers | Typical range (USD) | Median (USD) | Fees (USD) |
|---|---|---|---|---|
 Frontier | 2 | 342–358 | 350 | n/a |
 American | 17 | 393–409 | 397 | 110 (28%) |
 American Airlines | 18 | 387–492 | 432 | 116 (27%) |
 Frontier Airlines | 9 | 349–580 | 528 | 116 (22%) |
 Southwest Airlines | 116 | 544–808 | 561 | 20 (4%) |
 United Airlines | 40 | 470–578 | 568 | 45 (8%) |
 Delta Air Lines | 2 | — | 681 | 45 (7%) |
 Alaska Airlines | 1 | — | 819 | 10 (1%) |
Where do the best St Louis → Phoenix prices come from?
We checked direct airlines, travel agencies, and meta-search for this route. On this route the lowest median came from meta-search sources, but the cheapest channel shifts by route and date — which is exactly why a live search across all of them wins.
We compare every airline and the major booking sites but never disclose which — that's our edge. Prices are the ones we observed and aren't official data from any platform. Run a live search and we bring you the cheapest, wherever it is.
Key facts: St Louis to Phoenix flights
- Full-service carriers on St Louis–Phoenix cost 1.2x more than budget airlines (USD 580 vs USD 480 median; overall median USD 561).
- F9 charges 11.6x more in ancillary fees than AS — USD 116 vs USD 10 avg per booking.
- The same route priced USD 420 apart depending on where it was booked — the lowest median was USD 365. We search every airline and the major booking sites at once so you always see that lowest price.
Frequently asked questions
- How much does a flight from St Louis to Phoenix cost?
- Based on 205 offers analyzed, St Louis to Phoenix flights range from USD 340 to USD 884, with a median price of USD 561. Search for your specific dates →
- What hidden fees should I expect on St Louis to Phoenix flights?
- On average, ancillary fees (bags, seat selection) add USD 46 to the base fare on St Louis to Phoenix flights. See itemized fees for your itinerary →
- Which airline is cheapest on St Louis to Phoenix including all fees?
- Frontier has the lowest median fare on St Louis to Phoenix at USD 350 (median across 2 offers in our snapshot). Check which airline wins on your dates →
- Which booking site has the cheapest St Louis–Phoenix flights?
- It depends on your dates — no single site is always cheapest. We search every airline and the major booking sites at once (travel agencies and meta-search included) and surface whichever is lowest; the best median in this snapshot was USD 365. Run a live search and we'll find the cheapest for you →
- Why do prices vary so much on St Louis to Phoenix routes?
- St Louis to Phoenix has 8 airlines competing, creating a price range from USD 340 to USD 884 across 205 offers. There are two distinct fare clusters on this route: budget options and premium fares. Find where your trip lands in the distribution →
8 airlines, two price clusters — find which fits your budget
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