Hi I am looking to control the number of loyalty schemes I use. Existing being Flying Blue (KLM) ideal for my local airport UK midlands for flights into Europe and onwards, about 30,000 miles.
Then long haul BA, along with the Amex credit card and 241 etc.
I am finding this restrictive and find myself using other airlines and about to book a flight business class for two with KLM from my local airport to San Francisco which works with my flying blue. But noticed one of my flights is with Delta and they have a link with Virgin.
So I am wondering if to change from collecting my miles though flying blue and change to Delta as this will also give me a link with Virgin without having to have another loyalty card. What advice and comments can anyone please give if this makes sense?
E.g. Can I collect all through the delta Sky miles (star alliance + Virgin) then also us the rewards across the same airlines without losing too much?
Can I consolidate the existing Flying blue miles so they are not lost?
Plus I could join the business versions in the same way Blue Biz or Delta Sky bonus?
Any comments and feedback please, Thanks A

I can't comment on most of these issues, but I do know that redeeming award miles at reasonable rates on DL is found by many people to be extremely difficult. My own limited experience confirms this. In the USA, the frequent flyer programs offered by UA and AA are generally considered superior.

The Delta/Virgin alliance is so new that I would not hope that the availability of awards (if that is important to you) would be any better than the notoriously bad SKYPESOS with Delta. I am telling you I want to pull my hair out, no one way awards, which would make a difficult program a little easier to use adn find availibility. I accumulated 190,000 through my Suntrust debit card, but hope to soon retire it as it is twice as expensive per year as the AMEX delta card ($12 a month PLUS $75 a year for the 1:1 mile accumulation.) On the lpus side, it's the only card I know of that will give you credit for debt card purchases (think COSTCO, Amex only, if you don't have an AMEX car, which until recently I did not.) Proceed with caution with the DL program is all I am saying. Happy flying!

European-origin awards on Delta come with a redemption fee. OP, since you are based in Europe, this may reduce the utility of SkyMiles for you.

Also, miles are not like currency, where you can take pounds and convert them to euros or dollars. Flying Blue miles are not convertible to Delta SkyMiles.

Thanks for your comments, looks like I would be better off sticking with KLM for now and see what happens in the future.

Remember that it's extremely hard to find TATL availability for KLM or AF flights with DL miles, even though phantom KLM availability sometimes appears on delta.dumb. You cannot book these award tickets, nor can DL phone agents.