Viking probably has many convoluted arrangements with their air partners.
For example, paid extra for “premium economy” to Iceland from the US, with a return from Norway. This was above free air.
US flights are on Delta in Comfort +, transatlantic on Icelandair in Saga Class, returning from Europe on Delta in Premium Economy.
For my premium economy flights, Icelandair has me in their Saga Class - Viking did not call it business.
I was not given any alternatives on MVJ when Viking booked nor ticketed my flights.
Very satisfied for the $1,099 I paid.
Best I’ve found on my own is nearly $4,000