If you're involuntarily bumped from a domestic flight and land two or more hours after your original arrival time, airlines owe you cash compensation up to $400. The New York Times suggests if you have time to spare and volunteer to hop on the next available flight, you should negotiate for the maximum in-flight vouchers.
Getting bumped doesn't sit well with all travelers, so for the best chance of keeping your seat, check in as early as possible. Discounted ticket holders are the first to be bumped from flights — the cheaper your seat, the less valuable you are to the airline. Keep in mind that if you are bumped and arrive within an hour of your original arrival time, or if a smaller plane flies in place of the original larger plane, the airline owes you nothing.