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How to make the most of your airline miles
Airline miles can be tricky to understand, but CNBC Select offers five ways you can maximize your travel rewards to save on your next flight.

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If you frequently fly for vacation or work, redeeming miles can help you reduce the cost of travel — or eliminate it altogether.

Co-branded airline credit cards offer miles that can be redeemed for flights with a specific airline. Travel credit cards offer points or miles that can be transferred to frequent flier programs, applied as a statement credit or used to book flights with your preferred airline, typically through the card issuer's special travel portal.

Airline rewards can be tricky to understand, and there are a few steps to take to make sure you're getting the most value out of your miles or points, depending on the card you have. If you want to maximize the value of your airline miles and points (and have the time to do the work), you'll want to research all the various redemption options before you book your trip.

Below, CNBC Select reviews five steps to take to make sure you're optimizing your airline rewards.

How to make the most of your airline travel miles

  1. Choose the right credit card
  2. Take advantage of bonus offers
  3. Be flexible with travel dates
  4. Review reward transfer ratios
  5. Compare airfare prices

1. Choose the right credit card

If you haven't settled on an airline rewards credit card yet, you'll want to decide whether you want a co-branded airline credit card or a general travel card.

  • Co-branded credit card: Great for people who frequently fly with the same airline.
  • General travel credit card: Ideal for fliers who don't have a preferred airline since points and miles can be redeemed in more ways.

Once you decide which type of airline rewards card you want, your next step is to consider any annual fees and perks associated with the card. There are different tiers of credit cards, with some boasting $0 annual fees and others costing over $400. The higher the annual fee, the more perks offered by the card, such as lounge access and annual statement credits. Do the math to see if the perks outweigh any fees.

Many airlines have several co-branded card offerings, making it hard to choose the best one — there are a total of seven Delta SkyMiles Amex cards. Check out the standard benefits offered by all cards then look into premium perks to determine what benefits you want.

For example, the Delta SkyMiles® Blue American Express Card and Delta SkyMiles® Platinum American Express Card both offer 20% back on eligible Delta in-flight purchases, but the Delta SkyMiles Platinum card also offers priority boarding, first checked bag free and credit for Global Entry or TSA PreCheck. If you want premium perks, the Platinum card is the better choice.

2. Take advantage of bonus offers

Many airline and travel cards offer generous welcome bonuses after you spend a certain amount of money within the first few months of account opening. These offers are a great way to maximize the miles and points you earn.

For example, the United℠ Explorer Card offers 60,000 bonus miles after you make $3,000 in purchases in the first three months from account opening. (Offer ends 4/2/20.)

Read more: Chase launches new bonus offers on all United credit cards worth up to 100,000 miles

Co-branded credit cards may also run anniversary bonuses in addition to a welcome bonus. The Delta SkyMiles® Reserve American Express Card offers both through 4/1/20:

  • Earn 80,000 bonus miles and 20,000 Medallion® Qualification Miles (MQMs) after spending $5,000 in purchases on your new card in the first three months
  • Plus, an additional 20,000 bonus miles after your first anniversary of card membership

Read more: Delta Amex credit cards relaunch with new benefits and limited-time bonus offers

If you want to maximize airline rewards, you'll want to meet the spending requirements of welcome bonus offers. Just make sure you can do so while still paying off your balance on time and in full each month.

3. Be flexible with travel dates

When you're booking a vacation using points or miles, the more flexible you can be the better. If you limit yourself to say, the week of Thanksgiving, you'll likely have limited redemption options, or you'll have to spend more points in order to pay for your flight. Try to be flexible with the days you're willing to fly and book in advance so you have many choices.

Many portals will let you look at multiple dates at once, so you can compare dates and book when flights are least expensive. Also be aware that some airlines may set blackout dates, during which you can't redeem airline miles for award travel.

4. Compare airfare prices

Before you book airfare, you should compare prices and shop around for the best offer. While you may plan to use your points or miles to pay for your flight, there may be situations when it's a better idea to pay the full price for a ticket than use points or miles to cover your airfare.

Airline miles and points can only be used for airfare booked directly through the airline's website. That means you'll miss out on any promotions offered by third-party sites, such as Expedia or Priceline.

If you see a great deal on a third-party site, compare it with how many points or miles it will cost you if you book directly with the airline, then choose the option that provides the most value.

For example, CNBC Select calculated that American Airlines AAdvantage miles are worth an average 1 cent each. We compared the cash price to the amount of miles required to redeem for round-trip economy flights to several destinations. To find the estimated value of one mile, we divided the cash value of a round trip economy ticket (less the taxes and fees for redeeming miles) by the amount of points required to cover a reward ticket.

When redeeming AAdvantage miles, you should aim to redeem miles for a value of at least 1 penny. So if you plan to fly from New York (JFK) to Orlando (MCO) and the cash value of a ticket is $438 or the reward redemption is 32,000 miles + $11.20 in taxes and fees, calculate the value of miles to see if one mile is worth a penny.

That looks like ($438 - $11.20) / 32,000 miles = .013 or 1.3 cents per mile. This is above the 1 cent estimated value, so it's a good idea to book the flight using miles.

5. Review reward transfer ratios

If you have a general travel credit card, you can often transfer points or miles to participating frequent flier programs. The value of one point or mile varies, but the card issuer discloses the rate on its website. The best travel cards offer at least a 1:1 ratio.

If you have a Chase credit card, such as the Chase Sapphire Preferred® or Chase Sapphire Reserve®, you'll benefit from a 1:1 transfer ratio to leading airline and hotel loyalty programs. That means if you have 1,000 Chase Ultimate Rewards® points that's worth 1,000 partner airline miles/points.

But it's also key to note that Sapphire credit cards offer 25% to 50% more value on travel redemptions made via Chase Ultimate Rewards®. As a result, it may make more sense to book airfare through the Ultimate Rewards portal.

For example, if you have the Chase Sapphire Reserve® and redeem 10,000 Chase Ultimate Rewards® points for airfare via the Chase Ultimate Rewards® portal, they're worth $150. That's 50% more than transferring those points to a partner airline (where one point is worth a penny).

If your card has a transfer ratio less than the 1:1 rate, consider paying upfront for the ticket. For example, the Capital One® Venture® Rewards Credit Card offers a 2:1.5 rate for JetBlue (1,000 Venture or miles are worth 750 JetBlue TrueBlue points). It may make more sense to pay upfront for the ticket, then apply your Venture miles as a statement credit to cover the cost of the airline ticket.

Note that the value of statement credit redemptions vary by card issuer and you should only redeem for a statement credit when one point is worth at least a penny (which is the case for Capital One).

The bottom line: Booking travel using credit card miles can be a great way to save money, but you'll want to do the research ahead of time to make sure that you're getting the most bang for your buck.

Read more: Capital One is adding new hotel transfer partners and improving JetBlue transfers

Information about the Capital One® Venture® Rewards Credit Card has been collected independently by CNBC and has not been reviewed or provided by the issuer of the card prior to publication.

Editorial Note: Opinions, analyses, reviews or recommendations expressed in this article are those of the CNBC Select editorial staff’s alone, and have not been reviewed, approved or otherwise endorsed by any third party.