I should have stopped when I got the start of the second paragraph heading:
"easyJet (2003) on dynamic adjustment to stochastic demand"
but I persisted to section 3:
At which point I would have run for the hills, except I'm already 700 feet up one of them.
But yes, the writer is clearly using the USA model where seating normally comes upon purchase, and most of the airlines walk you through the seating module as part of the payment process. BA only gives free seating to discrete groups of their passengers and so that whole section, and the basis drawn from it, won't work for BA. In economy, in Europe, BA isn't alone either, and not Basic fares have started to creep into the US system too, since the paper was written. However I'm generally able to estimate how full a flight is by looking at the bare bones seat plan and the fare buckets, but it's more magic than the formula above.
I'll keep looking out for more mistakes. If this is my final FT post, you will all know why.