Back pain and travel

When we travel in an airplane or car, we pretty much stay in a seated position for an extended amount of time.  Our body may be resting (which sounds nice), but it's also in a fixed position that keeps the hip flexors shortened and the posterior lengthened.  This wouldn't normally be that big of deal if our lives weren't already consumed with sitting at work and home already.  We can't change much about the way we work and travel, but the right exercise program can develop the musculature of the posterior muscles which can offset a potential pain environment.