Mandy said:We don't know if Masako is really ill or if the IHA is deciding that she is too ill to accompany Naruhito. For that matter, we don't know for how long the IHA has been playing this little game.
Additionally, Emmily, it was suggested somewhere on this forum that, just maybe, Masako would like to be with Aiko while she is young since this is, at least until now, her only child. It could also be that Masako doesn't want to travel with Naruhito on the same plane to avoid Aiko having to be raised without she or N's guidance. Whatever the reason...the IHA sure makes it look as though she is "too ill".