Airplanes hit rough air pockets, car bump and bounce, ships, well ships go up and down a whole lot so we need to talk about motion sickness.
If you know your kid is prone to motion sickness, go easy on the pre-flight snacks (though we found a little something like crackers or bread in our daughters' tummy was a good thing). Anything greasy or otherwise hard to digest can make things worse. For some children, motion sickness medicine might help; see your doctor.
On board, looking at a stationary object can sometime help. Lots of people will tell you to look out the window, but sometimes staring at a rolling sea does not seem to help so much. Reading or looking at books always seems to have made it worse for our kids, though often the diversion of a story told can help.
Some kids want to throw up, some start sweating. Most kids want to throw up. If deterrence fails, make sure you have a target in mind if push comes to puke. The default position"Ã¢â€š¬throwing up on Dad"Ã¢â€š¬usually is not what you want.
On a plane there should be a bag in the seat pocket in front of you. Well-prepared Moms and Dads will have a ziplock back in a purse or backpack ready for trouble. Sad to say, we have in an emergency caught a blast in a drinking cup (it was a big cup) and on a plate. As a final defense, pull up the child's shirt to make a basket and catch what you can. The goal is to limit the items of clothing messed up of course.
Even on an airplane, you can rinse things off in the toilets and should do so. Fourteen hours on a plane and even a little puke will smell real bad, so salvage what you can. Once after our daughter threw up twice in one flight (thus negating the spare shirt we brought along in knowing preparation for the first volley) we had her sit without a shirt all wrapped up in an airline blanket. It wasn't pretty but it worked well enough.
On the other end of things, the following is an actual quote from a press release for airline vomit bags you buy yourself and take with you instead of the little paper bags. I quote “Chuckie Bags are airline quality, leak resistant sick bags. Our Brand New product is the only one of its type in the UK and we believe Chuckie Bags will successfully sell in an up to now untapped market.” I don't even want to think about what stuff might be inside that untapped market but if you want to tap in, be my guest.