Implement the commands for CourseAir, testing each and debugging as you go:
show_passengers(FLIGHT) - A list of passenger names and addresses
on the flight.show_passengers(FROM, TO) - The same, but starting with FROM,
TOshow_flights(FROM, TO) - Show direct flights and two hop connections
between FROM, TOlook_for_mayhem - The Roger Rabbit evil doers want to stop
toon mayhem on flights - they suspect it occurs when either 2 toonsville residents
or 2 ducks are on the same flight. Show these potential trouble flights.