I don't know and aware of transit Visa. I only know that I would need it if I stay for short visit in the transit country during layover. May be Etihad changed the rule now. Or may be you are just shooting stars with your overly imaginative and curious thought?
Who would ask for Transit visa when destination is US and layover is less than 24 hours and passengers ain't even traveling outside the airport for short stay requiring them to have transit visa?
Bro, get this one thing straight up, Etihad sucks. Listen to what your Uncle has to say once he arrives to you.
And, if you still don't understand what am yapping about, you can consider me 'I am jhyap'. That the best favor you can do to yourself.