The only trip I've taken in the three months I've been shaving with straights has been by plane. Not wanting to risk any of the straights I had at the time to loss via TSA bag checks or luggage handlers/inspectors, I packed an old DE, a couple of DE blades, a WeeScot brush, and some Truefitt and Hill sample packets.

Next I travel by car for more than a day or two, it'll be:
  • a straight
  • a Tony Miller practice strop (which I've hung onto specifically to use as a travel strop)
  • my WeeScot brush
  • sample size cream or soap I have on hand at the time

...no bowl or mug as I tend to just face lather when travelling - like to keep my bags as light and minimal as possible.