With storms, snow, delayed flights and industrial action all expected in what could be the busiest holiday travel period on record, Americans set out in hope rather than expectation of a stress-free journey this week.

Two major storm systems may bring travel chaos to much of the country, dumping rain and snow across communities and major cities. Already 17,000 flights have been canceled or delayed because of severe weather across the country since Friday.

The FlightAware website’s real-time…