If you want a pretty decent overview of the state-of-play that doesn't come from some journo hack (did someone really quote an order-order article? really? unbelievable) then this is quite good:
https://www.gbaa.de/fileadmin/pdf/20...s_Aviation.pdf
Disclaimer: It's from the Germans, so no doubt whichever highly intelligent individual liked order-order will say this is automatically wrong as it's not British
