I’ve written before about how you can use Air France/KLM Flying Blue miles to redeem one-way awards on Delta (even though Delta does not allow you to book one way awards with Skymiles). I pointed out that this was useful for domestic travel and for one-way travel to Europe (they don’t charge a fuel surcharge on Delta flights to Europe, though oddly enough they do charge the surcharge for the return trip).
I hadn’t noticed before, but Flying Blue also does not charge a fuel surcharge on Delta redemptions to Central America, South America Australia or Asia IN EITHER DIRECTION. Flights on Delta metal are 30,000 miles round trip (or, as with all, you can book a one way) to Central America; 50,000 round trip to South America; and 80,000 round trip to Asia. The online tool appears to have some trouble with business class redemptions on Delta, so you’ll have to call to straighten that out.
Also, don’t forget that Flying Blue is also an Alaska Airlines partner, so you can redeem just 30,000 miles round trip (or 15k as a one-way) for travel on Alaska to Hawaii — you’ll have to call to book, as this redemption isn’t available online.
The one-way option allows for some flexibility when you’re booking since you can find availability in one direction and use miles from another program for the other direction (sounds obvious, but lots of people forget about that). You can get miles into Flying Blue from both Membership Rewards and Starwood (with the usual 5k bonus for 20k transfer).
Delta doesn’t have great availability, but using Flying Blue miles does basically open up a good chunk of the world for one-way award travel in both directions on Delta with no fuel surcharge. Always nice to have more options.