While some have criticized the Delta SkyMiles program for its less-than-great mileage options, they do offer some inexpensive domestic award flights that make using this program worthwhile. On top of that, Delta is a member of SkyTeam Alliance, meaning you can redeem your SkyMiles with any SkyTeam Alliance member. These airlines include:

Aerolíneas ArgentinasITA AirwaysAeromexicoKenya AirwaysAir EuropaKLMAir FranceKorea AirChina AirlinesMiddle East AirlinesChina EasternSaudiaCzech AirlinesTAROMDelta Air LinesVietnam AirlinesGaruda IndonesiaXiamenAir

Unfortunately, Delta was one of the first airlines to get rid of its public award chart and change to a dynamic pricing system for award flights.