This thread, while having some valid points, certainly verges on the atas.

They’re not the only airline downgrading champagne though and I suspect champagne houses are probably able to sell at higher prices than they would sell in bulk to airlines which leads to airlines buying cheaper champagne.

More expensive is not always an indicator of quality though - case in point, Piper Heidsieck’s 2012 vintage was selling for the same price as Veuve Clicquot NV here and Piper 2012 is much much better.