I flew in all of Delta Air Lines' cabin categories last year, from the economy main to Delta One. Some upgrades had drawbacks ... Plus, I often monitor the seating chart before international ...

Everything you need to know about complimentary, mileage and certificate upgrades when flying Delta Air Lines.

Most coach fares will cost you 15,000 miles and $75 to upgrade to business class. How much does it cost to upgrade on Delta? There is a $359 and $399 upgrade fee for T, U, V, and X fares. The ...