If you are bumped in this manner, Department of Transportation rules require that you be compensated, and the compensation is generous. Indeed, in 2011 the agency doubled the eligible compensation that involuntarily bumped passengers are entitled to receive. If the airline is able to get you to your domestic destination within two hours of the original arrival time, you are entitled to a cash refund of twice the cost of the one-way ticket to a maximum of $650.
If the involuntary bump lands you in your destination more than two hours late, you are due an amount equivalent to four times the cost of your ticket to a maximum of $1,300. The rule is the same for international flights, except that the DOT defines "short" international delays (which net up to $650) as those that get you to your destination within four hours of the original arrival time. Those that get you to an international destination more than four hours late entitle you to $1,300.
It's worth noting that most airlines will try to pay this fee in travel vouchers, but you can demand a check. The DOT regulation requires the airline to give you cash compensation if that's what you prefer, Hobica said.
Flight rights: What you're due when bad things happen - CBS News