Some Flight 1549 passengers have reportedly "lawyered-up."  What legal claims do they have?Flight 1549  Putting aside the question of whether pursuing the claims is the right thing to do — some say they should simply count their blessings — do the passengers have any claims to begin with?

Well, it depends on the law that applies.  For example, under California law, a passenger would first have to show that the accident was caused by the airline’s negligence.  From what is known so far, that seems unlikely. If, however, the passenger succeeds in proving negligence, he would be entitled to compensation for any physical injuries he sustained as well as compensation for the emotional distress he suffered. 

What if the passenger suffered just emotional distress and no physical injuries? Again using  California law as an example, if the airline was negligent, the passenger could recover for the emotional distress, as long as that the emotional distress was "serious."  (Not much question about that.)

What if the passenger had a foreign destination listed someplace on his itinerary?  That would change everything. Even though the flight was domestic, the Montreal Convention, an international treaty governing airline liability, would trump state law.  The passenger would not need to prove the airline was negligent to recover.  It is enough that a passenger’s injuries were the result of an "accident."  The airline would be automatically liable. But under the Convention, the passenger would not be entitled to compensation for mental injuries, regardless of how "serious", unless he also suffered at least some physical injury.