Answered by The Penny Pincher
As far as I know you cannot not use your Delta miles on Thai Air unless you go through some exchange process like points.com but be ready to lose miles in the conversion.
A better choice is to fly Singapore Airlines which is a top notch carrier. You can redeem 60,000 120,000 or 140,000 miles for an economy, business class or first class respectively. Take a look at this link
In my opinion both the business class and first class award are excellent value as a first class ticket can cost $10,000.
More like this: Air Miles, The Penny Pincher, Upgrading