Best way for flexible eu-us flight
 

Hi all, I booked flights for US-FCO-US roundtrip using DL miles but flights keep getting canceled. So now I used UA miles to book an LH/LH flight for US-FCO (77k miles per person), but the return flight is still not booked because I have no more UA miles. I have lots of MR and UR points that can be transferred once it gets closer to travel date, also have about 120k DL miles, 200k BA miles. What's the best way to book a return flight? I looked at NH miles but surcharge is too high for most aspirational carriers. Right now I'm just looking at AC miles to fly back, they're 70k miles per person. I have some flexibility too to fly out of other Italian cities rather than FCO. Any recommendations welcome!

I have no suggestion for what miles to use, but I would warn you that DL award flights originating in Europe come with a hefty surcharge. The surcharge is not applied to RT transatlantic flights that originate in the USA, but it would be applied in your case.

You can use your BA Avios to book AA flights. They serve FCO and MXP on their own aircraft, and those flights don't have any surcharges.

AA awards seem to be scarce in premium cabin…

I don't know what an aspiration carrier is, but the difficulty you (and many others) have is balancing the need to book tickets early while there is still availability, and the uncertainty of whether these flights will be cancelled. I'm not sure anyone here can give any meaningful guidance, as cancellation is at the whim of the airline. If all you need is a flight from Europe to the US, I'm sure finding something close-in should not be too much of a problem, and if a cancellation does happen, you'll be rerouted back anyway.

When your DL award flights are cancelled, DL should rebook you on an alternative DL flight for no charge. If needed, DL can open award inventory on its own operated flights, but not on partner flights.

I wonder whether part of the problem is that your itineraries included AZ (has been a SkyTeam partner IIRC with some codeshares) flights as AZ will "disappear: on October 15th.

Call DL and get RT award tickets on DL (or AF/KLM if connecting flights within Europe are needed). If your tickets were improperly cancelled without your consent, DL should make this right and give you new award tickets for the original price in miles.