Ryanair Fleet Replacement?
Of the 410 Boeing 737-800NG's in the Ryanair Group fleet, my understanding is that 154 of them have the Boeing Sky Interior (BSI), the oldest of which is just over 9.5 years old now.
Currently Ryanair Group still has 29 Boeing 737-8200's for delivery plus the 300 MAX10's they're hoping to start getting from 2027 until 2034 (it's anyone's guess as to how realistic that is).
Theorectically, if Ryanair were to get rid of the A320 Lauda fleet plus all of the Boeing 737-800NG's without BSI with all the current orders fulfilled by then, my calcultation is that would take the total group fleet from 624 currently to 654 by 2034. That seems fairly modest still for Ryanair albeit 300 aircraft in theory would be larger MAX10 aircraft, so the seat capacity growth would be much higher. Bear in mind also by then, even the first NG's with BSI will be 18-19 years old, so wouldn't seem an unrealistic threshold for older aircraft to be retired.
Aircraft delivery delays are of course meaning most airlines are having to hold onto older aircraft for much longer than they'd like to. But Ryanair, even with their significant order book, doesn't as yet seem to deliver an awful lot of scope for fleet replacement. Of course Ryanair could make an entirely new order to help replace older frames, but how realistically could Boeing deliver that along with existing orders? Ryanair will no doubt be hedging their bets also on other airlines cancelleing orders which they would want to take, but without that, I think we could still be seeing NGs in the Ryanair fleet probably well into the 2040s!