Question 1

What airlines fly to St. Louis?

Accepted Answer

United Airlines, Delta and Southwest are the top three most popular airlines that fly to St. Louis from Idaho according to our data. United Airlines is the first choice among our users, with 38% of people opting to fly with this airline when traveling to St. Louis. Keep in mind that there are 5 different airlines that fly to St. Louis on a routine basis, so you have a few additional options to choose from.

Question 2

How long does it take to fly to St. Louis?

Accepted Answer

Flight times from Idaho to St. Louis vary, but if you’re flying out of Idaho Falls and flying into St. Louis (one of the most popular routes), then the duration is 4h 26m on average. Another popular route from Idaho to St. Louis is flying from Boise to St. Louis, which will take roughly 4h 57m. Keep in mind that layovers or delays could extend your travel time.

Question 3

Can stopping save me money on Idaho to St. Louis flights?

Accepted Answer

You could potentially save up to 41% on your flight if you consider stops on a Idaho to St. Louis flight.

Question 4

What is the cheapest airline that flies from Idaho to Lambert-St Louis?

Accepted Answer

American Airlines, Alaska Airlines, and Frontier are the most popular carriers operating from Idaho to Lambert-St Louis

Question 5

What is the cheapest month to fly to St. Louis?

Accepted Answer

In general, September is the cheapest month to fly from Idaho to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $294. The month of April is another great option to travel to St. Louis, with average flight prices from Idaho averaging around $342.

Question 6

How far in advance should I book a flight to St. Louis?

Accepted Answer

You are more likely to see cheaper flights to St. Louis from Idaho when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $409 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Idaho for as low as $313 on momondo.

Question 7

When did momondo last update prices for flights from Idaho to Lambert-St Louis Airport?

Accepted Answer

Prices for flights from Idaho to Lambert-St Louis Airport are refreshed on a daily basis.

Question 8

How many operators does momondo search for flights from Idaho to Lambert-St Louis Airport?

Accepted Answer

As of April 2026, there are 5 operators available to choose from for flights from Idaho to Lambert-St Louis Airport.

Question 9

How old do you have to be to fly from Idaho to Lambert-St Louis Airport?

Accepted Answer

The minimum age a child must be to fly alone is five but airlines that offer an unaccompanied minor (UNMR) service will have their own age restrictions, including rules around flight length, timings, and stopovers. We always recommend checking with the individual airline you are booking with to travel from Idaho to Lambert-St Louis Airport.

Question 10

What documentation or ID do you need to fly to Lambert-St Louis Airport?

Accepted Answer

The required travel and health documents for your Lambert-St Louis Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's license and a passport valid for six months after your intended arrival at Lambert-St Louis Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

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