There are no mandatory compensation laws for delays in the US. Airlines have a Contract of Carriage which describe their liabilities in the event of delays. These can be found on their website. They generally limit their liability to providing you with a hotel (and transportation to the hotel if they do not provide a shuttle) when delayed overnight at a connecting airport and only when the delay is not due to reasons outside their control (such as weather). Note, you need to go through the airline for these (don't assume they will reimburse if you arrange on your own). They do not provide for transportation at your origin or destination airports or other incidentals (like food) unless they divert you to an alternate nearby airport where they will provide ground transportation to your original destination airport. As noted above, they may provide some miles or a future transportation credit as a goodwill gesture.