While choosing a flight, it is not always that lower cost is the only objective; in many cases, a user may wish to choose flights having lower durations and other such parameters.  This problem of multiple objectives is solved by the skyline queries in databases.  A skyline set of objects are those that are not worse than another object in all the preferences.  For the flight example above, it is useless to return a flight to the user that has larger cost and higher duration than another flight.  It is not a skyline and the user will never be interested in it.  The project aims to extend the skyline queries to probabilistic and distributed databases.  The aim will also be to handle aggregate attributes such as total cost and total duration in multi-hop flights.