Hi Lynne,
I'm also in Dublin and have flown from Dublin Airport lots of times,usually without a hitch. Whatever airline your son is travelling with he will have to ring them after booking his tickets and make them aware of all his details, type of chair, weight etc. There will be no problem getting him into his seat as he will be lifted off the portable chair that brings him onto the plane by two airport staff, one will grab his legs and the other under his arms, and in a jiffy he will be seated comfortably.
Hope he has a great time in the Big Apple.
McTavish
