(board person1 plane1 city0)
(zoom plane1 city0 city1 fl4 fl3 fl2)
(debark person1 plane1 city1)
(board person3 plane1 city1)
(zoom plane1 city1 city0 fl2 fl1 fl0)
(debark person3 plane1 city0)
; cost = 6 (unit cost)
