[pisarzp]

It's usually at least 3-4x, not double. On some routes, it's even up to 10x.

Also, here as a couple, you might have this just for 50% more (booking 3 seats instead of 2; assuming price per seat is the same)

[mason55]

Yeah First class on Chicago to Bismarck might be 2x but JFK to Heathrow is an easy 10x

[Zombieball]

You just need to look for flight sales (like you would for an economy ticket).

Example:

JFK to FRA, business class, A380 lie flat: $1,996USD

https://www.flyertalk.com/forum/premium-fare-deals/1894422-s...

That’s only a 2.3x multiple of the $875 economy fare.

[willyt]

Norwegian is ~$200 single New York - London