Originally Posted by pjfoley1
Keep in mind that you can't UG an insULT fare witha companion UG on DL.
"You and a travel companion may both enjoy the comfort of our First or Business Class cabins. Use your unlimited complimentary upgrades to upgrade a SkyMiles member of your choice, as long as he or she is traveling with you on the same flight. Please note that General members flying in L, U or T class are not eligible for companion upgrades."
http://www.delta.com/skymiles/about/....jsp#companion
A lot depends on availability of FC seats. I've upgraded my family members on a few flights with them holding insULT fares. Once I got two upgraded traveling on award tickets. Sometimes ask and you will receive!