Disposable inserts are a great option for those instances when you do not have access to washing facilities, or times when you need a break from cloth. Simply place the insert in a cover,* and secure around baby (shells are easy to wash in the sink, so don't worry about those hampering your travel style).
*While both Flip and GroVia make covers and disposable inserts, you do not need to use their respective covers. Rather, you can mix and match any insert to any cover - the only stipulation is that your cover must fit baby well - if there are any gaps in the legs or waist you will likely end up with leaks.
Looking for disposable liners (aka - something to protect a cloth diaper's surface)? Check out these.
Abby adds - Until my daughter was around 20mos, we used one GroVia or Flip insert in her daytime diaper, changing every 2-3 hours. At 25mos she now holds her bladder for so long that we need a lot of absorbing power. For her daytime diapers I stick a GroVia insert in the shell, then layer a Flip insert over the top (with part of the Flip insert doubled over in the heaviest wet zone). For nighttime I then add another Flip insert over the top of this. I know it sounds like a lot of inserts, but she also holds her bladder 4+ hours, so at the end of the day we only use 1 or 2 more a day than we did six months ago. Final note - using a Flip insert as a doubler for the GroVia works well, as the GroVia is backed with plastic, and the Flip insert is absorbent from front to back.