I've suffered with travel sickness all my life too. I avoid boats and buses at all costs but can manage front seat of the car, trains. Planes are hit and miss and I always make sure there is a sick bag within reach before take off because for a while, Ryanair stopped leaving them out!. I even feel queasy in a lift and normally take the stairs.
I swore nothing worked (tablets, seabands etc) and for years just suffered on but recently I've gone back to taking Kwells and they are definitely providing some relief. So maybe you could try again?
Hope you find something because it can really knock the sheen off looking forward to a trip.
Rebecca