When one of your friends or family members tells you that there are some really cheap plane tickets out there, let's not kid ourselves: They're usually talking about  Frontier Airlines.

The Denver-based airline is known in the industry as an ultra-low cost carrier. While people usually have strong feelings about flying in that segment, Frontier is the eighth-largest airline in the country — so they must be doing something right.

Want to fly for cheap? Read this before you book Frontier Airlines

Frontier Airlines was born out of a Continental Airlines work stoppage in 1993. One year later, Frontier was flying out of Denver bound for four destinations in North Dakota. The following year, the carrier added more routes and cities and grew from there.

RELATED: Frontier sale offers $20 one-way

If you've never flown Frontier or you're thinking of booking a ticket again in the near future, here are some important things to know about the carrier:

1. Where does Frontier fly?

Frontier operates flights to more than 80 destinations throughout the United States and four international destinations (Canada, Dominican Republic, Puerto Rico and Mexico). The company is looking to expand in the next few years. See their route map.

Before you book a flight to any of those destinations, here’s a general rule you need to know about this airline: Frontier allows you to fly with one free personal item (it needs to be able to fit under your seat). Other than that, carry-on baggage is going to cost you — but more on that later.

2. How is Frontier able to charge such cheap fares?

Frontier’s ultra-low fares are a result of its no-frills base packages. Frontier has two fares — called THE WORKS and THE PERKS — which allow fliers to get a price exemption on a carry-on bag and checked bag.

Here is how those two tiers break down:

Frontier

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When you see those super-cheap online deals that Frontier advertises, those are just base packages. There are a number of add-ons that a traveler may well incur. Here are some of them:

  • All reservations made through the call center will incur a $10 booking fee per passenger. This fee is waived for all frequent flyer members of the EarlyReturns ® Elite program on any fare.
  • To change your ticket, you'll generally be charged a $99 fee. (It is waived for customers who purchased THE WORKS).
  • If there's no change in the travel itinerary, Frontier will let you change the name on the ticket for $75.

3. Does Frontier charge for a seating assignment?

Frontier won’t charge you for a seat if you let the airline choose it during check-in (don’t bet on sitting next to family). Otherwise, be prepared to pay up.

There are two categories of seats — Standard and Stretch. You can choose a Standard seat for as low as $6 online up to 24 hours before your flight.

Stretch Seats range from $20 to $25 depending on if you buy them via online, call center or at the ticket counter.

You can buy a seat assignment when you check-in online within 24 hours of departure on your Manage My Booking page under the My Trips tab on the site.

4. How much does Frontier charge for baggage?

Like most airlines, Frontier charges for checked bags. The airline has six price tiers for bags, depending on when you travel.

Checked bags must be under 50 pounds and within 62 linear inches (length x width x depth). Bags over either of these two parameters will be charged $75. Warning: It is possible to be charged $75 twice for exceeding both weight and size requirements!

carryon bags graphic via Frontier.com
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Carry-on bags must be able to fit in the overhead bin and can be no larger than 24″ height x 16″ width x 10″depth (including handles, wheels and straps) and no heavier than 35 pounds.

If you arrive at the gate with a carry-on bag over the allowable limits, you’ll pay extra to gate-check the bag.

5. How do Frontier customers view the airline?

Because of its cheap fares, Frontier continues to come up in search results for cheap airlines. When it comes to customer satisfaction, Frontier came in next to last in the American Customer Satisfaction Index report that was released in April 2018:

Team Clark Newsletter Editor Sally recently flew Frontier from Atlanta to San Juan, Puerto Rico. This is what she said about the experience:

“The best part: No delays! (In fact, both flights landed early.) The worst part: The fees! Our overall experience was good, and the fares are too cheap to pass up! When booking with a discount airline, we always factor the fees and extras into the ticket before we book to make sure we’re actually saving money. We also make sure we’re willing to sit in less-than-comfortable seats for the entire flight.”

6. Is Frontier family-friendly to fly?

If you choose to pay for seating assignments, flying Frontier can be a breeze. Also, families with small children, take heart: When you’re traveling with a little one, a stroller, car seat and diaper bag can all be checked free of charge.

Have you flown Frontier Airlines? Tell Team Clark about your flying experience on FacebookTwitter or below in the comments section!

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