(refuel plane1)
(fly-slow plane1 city2 city0)
(board person4 plane1 city0)
(fly-slow plane1 city0 city1)
(refuel plane1)
(board person2 plane1 city1)
(debark person4 plane1 city1)
(fly-fast plane1 city1 city2)
(debark person2 plane1 city2)
(fly-slow plane1 city2 city0)
; cost = 10 (unit cost)
