If it exists at all, I'd guess it refers to the peak inbound dates and peak outbound dates surrounding the games.
And in which case, by definition, those flights should be going back (then out again) totally empty. Lots of predictions get made in the hype of something like the Olympics, y.o.y. figs for Sept / Oct onwards would be more interesting.
values it at £4.5 bn
Was that sum not spent on T5 alone? At that price, maybe Silver has a point about sending in the asset strippers and it being worth more closed than open. Surely LHR is a safe, long term bankable yield, unlike the fantasy projects these wealth funds are "supposed" to be interested in?