I did ponder that but I'm not sure how comfortable I'd find them after 12 hours and most of the in-ear noise cancelling ones have the boxes for battery which makes them a bit awkward to use for anything on the go.
I guess everyone’s experiences and ears are different. I have on-ears and they start to hurt after about 2hrs even without glasses. I like to lean against the wall of the plane whilst sleeping so over ears are a no go. I have not yet had any discomfort from in-ears after 6 or more 12hr flights.
I did ponder that but I'm not sure how comfortable I'd find them after 12 hours and most of the in-ear noise cancelling ones have the boxes for battery which makes them a bit awkward to use for anything on the go.