Cheap Flights from Philadelphia (PHL) to St. Louis (SUS)

Popular airlines from Philadelphia Intl. Airport (PHL) to St. Louis, MO (SUS-Spirit of St. Louis)

Alternative airports near St. Louis

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Lambert-St. Louis Intl. STL. Cheapest option available. Average driving time to city center is 20 minutes. Flights from $335
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $335

Frequently asked questions

How much does a flight from Philadelphia Intl. Airport (PHL) to Spirit of St. Louis Airport (SUS) cost?
Lock in a cheap one-way flight or cheap return flight from Philadelphia Intl. Airport (PHL) to Spirit of St. Louis Airport (SUS) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to find our cheapest flight deals on this route.
What is the cheapest month to fly from Philadelphia Intl. Airport (PHL) to Spirit of St. Louis Airport (SUS)?
is the least expensive month to fly from PHL to SUS. Avoiding peak travel times is often the key to finding a great deal.
What is the cheapest airline that flies from Philadelphia Intl. Airport (PHL) to Spirit of St. Louis Airport (SUS)?
Expedia's filter tool lets you easily compare airlines, flight times and fares all in one place. Tailor the search to your trip, then sort by "Price (lowest to highest)" to see which carrier offers the cheapest PHL to SUS flight.
How many flights per day from Philadelphia Intl. Airport (PHL) to Spirit of St. Louis Airport (SUS)?
Nonstop flights from Philadelphia Intl. Airport (PHL) to Spirit of St. Louis Airport (SUS) aren't available daily, so you'll need to take a flight with a layover. Explore your options with Expedia's filter tool. Enter your dates and select either "1 Stop" or "2+ Stops."
What day of the week has the most flights from PHL to SUS?
Generally you'll have the most choice when it comes to flights on a Friday. Tuesdays are often the quietest.* But this can change based on the time of year, airline and other factors.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Philadelphia Intl. Airport (PHL) to Spirit of St. Louis Airport (SUS)?
To avoid potential delays on the Philadelphia Intl. Airport (PHL) to Spirit of St. Louis Airport (SUS) route, travel before 3 PM. Flights after this time are 22% more likely to be canceled.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports do you fly into for St. Louis from Philadelphia Intl. Airport (PHL)?
Lambert-St. Louis Intl. Airport (STL) is the only airport in St. Louis with direct flights from Philadelphia Intl. Airport (PHL). Compare your options and find affordable fares on Expedia.
Is it cheaper to buy a plane ticket from Philadelphia Intl. Airport (PHL) to Spirit of St. Louis Airport (SUS) last-minute?
Booking your ticket from PHL to SUS just before your trip is generally more expensive. But if you're flexible with your departure dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book a PHL to SUS flight and hotel package?
Compared with arranging hotels and flights separately, booking a PHL to SUS flight and hotel package with Expedia could result in significant savings. Better still, having everything in one convenient place will take the hassle out of travel planning. Just pick your flights and choose from our wide range of stays, then tailor your trip with other add-ons like activities, tours and car rentals.
Can I cancel or change the date of my flight from Philadelphia Intl. Airport (PHL) to Spirit of St. Louis Airport (SUS)?
In most cases, you can modify or cancel your PHL to SUS flight. However, additional fees may apply, especially if you booked more than 24 hours ago. Check your itinerary for the airline's fees and rules on flight changes, or if you need further information, visit our Customer Service portal.

Travel information

Origin airport
Philadelphia Intl.
Destination airport
Spirit of St. Louis
Distance
827 mi

Book with confidence

Philadelphia to St. Louis Flights

The cheapest times to fly from Philadelphia to St. Louis

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Philadelphia to St. Louis are during the month of . You can find some of the cheapest flights from Philadelphia to St. Louis with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Philadelphia to St. Louis

Sunday is one of the best days to book for cheap flights from Philadelphia to St. Louis: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Philadelphia to St. Louis

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Philadelphia to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Philadelphia to St. Louis flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Philadelphia to St. Louis airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Philadelphia to St. Louis Flights

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*Available to One Key members.