Is it permissible to eat food from a Chinese airplane while I am traveling?

As for non-meat foods, there is no harm in eating them. However, meat is not permissible to eat unless it is known to have been slaughtered according to Islamic law, and that the slaughterer is Muslim or from the People of the Book. If there is doubt, or if most of those who slaughter in China do not slaughter according to Islamic law, then it is not permissible to eat, because the default ruling for slaughtered animals is prohibition.