Same here, stuck on "Pumping Sim Once" after it lets me create a campaign and setting all graphics settings to low. I did get past this point yesterday once, and flew a short mission, but today I'm once again completely stuck. My son, who has the same laptop as I do, is also stuck in exactly the same point. This is deeply frustrating.
For reference, these are Asus Aspire 5 laptops, upgraded to 32 GB RAM, otherwise pretty low on the specs, but it did work for me yesterday, and not today.