I thought you could put them in storage on the plane when you board that's why they have the limit for dimensions of pushchair when folded?
We got the kinderkraft pilot 2 which is cabin approved size and will be taking that on to our BA flight
I believe most airlines let you take to the aircraft and then you have you leave at steps. I’m flying with Ryanair tomorrow and have an IATA pushchair but can’t take it on board. Would highly recommend the Bugaboo Butterfly.