So Who The Heck Is it?

Airbus snuck in (a little unsubtly) an unnounced order for 52 A320 class aircraft.

Speculation is rife.

So here is a short list of my candidates!

United
Ryanair
Delta

I probably have it wrong but its nice to purely speculate.
When its revealed who it is - then I will give you my reasons

BTW there is a caveat. I am assuming these are firm orders. Airbus tends to have a habit of having somewhat flexible orders.

Cheers