Using miles to upgrade a coach ticket
 

I can't seem to find this information anywhere...

If I purchase a coach ticket on Delta and upgrade it using miles (assuming the ticket can be upgrade) - would I still earn the coach-level miles on the itinerary or would I earn nothing for this (paid) itinerary because of the upgrade?

For domestic it has to be a K fare or higher to use miles.

International M or higher.

You still earn the SM/MQM's on the fare you originally purchased.

mlad1101 - thanks, that's very helpful! This would be a continental US to Hawaii trip... so K fare?

K fare or above. No L, U, T fares. And when you do buy a K fare, they will only allow a certain number of upgrades so you should make sure that there are upgrades available for your flight. For US to HI, a lot of people will try to upgrade with miles, so be sure you call a DL customer service rep to check for upgrade availability before buying the higher priced K fare.

Using miles to upgrade is generally a poor use of miles - many times you can find a discounted BE fare that is almost the same as the coach fare class required to use miles to upgrade.

I am probably the only person then who can't find BE fare's at the price of coach.