Airline responsibility with flight changes

Had you not booked as you did and taken out insurance, you would have had to buy a last-minute fare to the next port of call at considerable expense, and there would have been no compensation at all for your missed days.

According to the U.S. Department of Transportation website, the compensation maximum is $1,300 if the airline arranges substitute transportation arriving at your destination within more than two hours on a domestic itinerary or four hours on an international one. And you get to keep your original ticket and use it on a future flight. But, "If the airline must substitute a smaller plane for the one it originally planned to use, the carrier isn't required to pay people who are bumped as a result. In addition, on flights using aircraft with 30 through 60 passenger seats, compensation is not required if you were bumped due to safety-related aircraft weight or balance constraints." So US Airways wasn't required to pay you anything at all.