Refueling Planes planning domain.
Consider that we need to plan how to refuel planes in order
to get to far destinations. For simplicity we have several
airports in the line and several planes with certain fuel
capacities. Planes can travel between the airports. A plane
consumes certain amount of fuel to travel a unit of distance.
Some extra fuel is also necessary for landing and taking-off.
Each airport has an unlimited source of fuel and planes can
refuel at the airport. The important ability of planes is to
transfer fuel from one plane to another plane in-flight.
The task is typically to get a fleet of planes from one
airport to some distant one. The task is especially interesting
when planes need an intermediate landing on some
middle airport or in-flight refueling.