C-bands are probably worth a go, if only for their placebo effect.
Interstingly your daughter gets sick prior to any motion, somehow she's been conditioned into this state, and this may be worth exploring. Anyone else in the family puke prior to departure?
Failing these measures, it may be worth having a chat with your GP/Pharmacist, as some medicines may help-the "bonus" sedative effect may also be useful.
And remember, the sickness is distressing, but unlikely to harm her health-have a good holiday
