Your miles/points can also be used to upgrade an already purchased ticket to a premium cabin.
How do I book a redemption flight?
First, you will need to accumulate a large number of points/miles on your frequent flyer program. Once you have that, you will only be able to book a redemption flight on an airline’s website.
Remember, not all flights are available to purchase with your points. Carriers often only put flights during off-peak periods available for redemption.
You can often use your points to book a redemption flight with a partner airline. For example, a United Airlines MileagePlus member (with enough miles) can book an Air Canada redemption flight.
Can I book a redemption flight using ONLY points/miles?
Not really. Despite airline stating you can book a flight with your miles, you do have to pay a little cash on top.
Your miles are only used towards the base fare component of the ticket. There is still the tax and surcharges that needs to be covered. This can range from a few dollars to hundreds of dollars depending on the flight.