Yes, Turkish Airlines allows members of its Miles&Smiles frequent flyer program to use their accumulated miles to pay for extra baggage allowance. This can be done quite easily through the Turkish Airlines website, mobile app, or by contacting their call center/sales offices. When you manage your booking online, you will see an "Extra Baggage" option where you can choose to pay with either a credit card or "Miles." The "mileage cost" for baggage depends on the specific route (domestic vs. international) and the total weight or number of pieces you are adding. It is important to note that you must have enough miles in your account to cover the entire cost of the extra baggage; partial payments with miles and cash are generally not allowed for this specific service. Additionally, this option is usually only available for flights operated entirely by Turkish Airlines (or AJet), and it may not be available for certain codeshare flights. Using miles for baggage is often considered a "low-value" redemption compared to business class upgrades or award tickets, but it is a very practical way to use up "orphaned" miles that might otherwise expire.