An airline's liability for a passenger's injury or death is most often determined by state law. But if the passenger's trip includes a stop in a foreign country, then the airline's liability is controlled entirely by international treaties. The treaties are known as the Warsaw Convention and the Montreal Convention.
The treaties also govern a passenger's claims for injuries occurring on a domestic flight, as long as a foreign destination was on the passenger's itinerary. That means that state law may govern the claims of one victim of an airline disaster, while a treaty may govern the claims of his friend in the very next seat. Because different law applies, one victim (or his family) might be entitled to compensation from the airline, and the other not.
Which is more favorable for the victim -- state law or the treaties? It depends on the circumstances of the case. For example, if state law applies, to successfully sue an airline, the passenger must prove that the injury occurred because the airline was "negligent" or, in other words, "careless". But if a treaty applies, the passenger need not prove the airline was negligent at all. If a treaty applies, the passenger need only prove that his injuries were the result of an "accident."
What if a flight attendant accidently pours hot coffee on you and you are seriously burned? Under state law, you could recover from the airline, if you prove the flight attendant was careless. Of course, if the flight attendant splashed you on purpose, you would be entitled to compensation as well. But what if the treaties apply? Can the flight attendant's intentional act be considered an "accident"? Courts have struggled with this sort of question, and offer no clear-cut answer.