I am having to book an urgent business class flight today from Brisbane-Singapore-Frankfurt-Malta then back from LHR-Singapore-Brisbane (costing $10,000 - no choice in the matter). SIngapore Airlines and LUfthansa. I will have to go to USA next year and already have 400,000 velocity points - hoping to use them for USA flight. Do I hand over my velocity number for the Malta flight or should I join Kris flyer to get SIA points.
Assuming that you’re flying to Frankfurt, and back from London, on Singapore Airlines aeroplanes, you’ll be able to credit those flights to either Velocity or KrisFlyer.
I’m afraid that you won’t be able to credit your Lufthansa flight from Frankfurt to Malta to Velocity, even if it’s a codeshare (ie. it has an SQ flight number on your ticket). You can only credit Singapore Airlines operated flights to Velocity. So yes, I would agree with your suggestion that you join KrisFlyer and credit your points for that flight to them.
To be honest it’ll probably be easier and less finicky to simply credit your entire trip to KrisFlyer.
Hope this helps!