A great resource over at COPD.net on the safety tips of travelling with oxygen.
car travel with oxygenDo’s

  • DO fill the portable tank carefully, if using liquid oxygen. Liquid oxygen is extremely cold and can injure your hands, if frost should develop.
  • DO carry your portable tank only in the case supplied with it.
  • DO use a cart or holster to carry portable oxygen cylinders.
  • DO keep your oxygen delivery system out of the bright sunlight or other heat sources.
  • DO secure your tank, cylinder or portable concentrator so it does not roll around in the car. Liquid tanks should never be laid on their sides; portable cylinders may be.
  • DO bring extra batteries to power your concentrator.

Don’ts

  • DON’T put a portable tank inside a backpack or other carry bag.
  • DON’T place your tank, cylinder or portable concentrator in a car trunk or other tightly enclosed space.

There are quite a few DO’s for you to remember and t is always best to be prepared before embarking on a week or two away on holiday. Any advice needed on arranging oxygen please do just speak with the team at OxygenWorldwide.
 
ref: https://copd.net/living/traveling-with-oxygen/