写一个飞机订票系统可以具有录入，查询，订票，退票等功能

好的，以下是一个简单的飞机订票系统的Python代码示例：

class Flight:
    def __init__(self, flight_number, departure_date, departure_time, arrival_time, origin, destination, seats_available):
        self.flight_number = flight_number
        self.departure_date = departure_date
        self.departure_time = departure_time
        self.arrival_time = arrival_time
        self.origin = origin
        self.destination = destination
        self.seats_available = seats_available

class Booking:
    def __init__(self, flight, passenger_name, seat_number):
        self.flight = flight
        self.passenger_name = passenger_name
        self.seat_number = seat_number

class FlightBookingSystem:
    def __init__(self):
        self.flights = []
        self.bookings = []

    def add_flight(self, flight):
        self.flights.append(flight)

    def search_flights(self, origin, destination, departure_date):
        matching_flights = []
        for flight in self.flights:
            if flight.origin == origin and flight.destination == destination and flight.departure_date == departure_date:
                matching_flights.append(flight)
        return matching_flights

    def book_flight(self, flight_number, passenger_name, seat_number):
        for flight in self.flights:
            if flight.flight_number == flight_number:
                if flight.seats_available > 0:
                    booking = Booking(flight, passenger_name, seat_number)
                    self.bookings.append(booking)
                    flight.seats_available -= 1
                    return booking
                else:
                    return None

    def cancel_booking(self, booking):
        booking.flight.seats_available += 1
        self.bookings.remove(booking)

# 示例用法
flight_system = FlightBookingSystem()

# 添加航班
flight_system.add_flight(Flight("AC101", "2022-01-01", "10:00", "12:00", "Toronto", "Vancouver", 10))
flight_system.add_flight(Flight("AC102", "2022-01-01", "14:00", "16:00", "Vancouver", "Toronto", 20))

# 搜索航班
matching_flights = flight_system.search_flights("Toronto", "Vancouver", "2022-01-01")
for flight in matching_flights:
    print(f"Flight {flight.flight_number} from {flight.origin} to {flight.destination} on {flight.departure_date} at {flight.departure_time}")

# 预订航班
booking = flight_system.book_flight("AC101", "Alice", "A1")
if booking:
    print(f"Booked flight {booking.flight.flight_number} for {booking.passenger_name} on seat {booking.seat_number}")
else:
    print("No available seats for flight AC101")

# 取消预订
flight_system.cancel_booking(booking)

该系统使用Flight类表示航班，Booking类表示预订。FlightBookingSystem类则用于管理航班和预订，并提供录入、查询、订票和退票功能。在示例用法中，我们添加了两个航班，搜索了从Toronto到Vancouver的航班，预订了AC101航班并取消了预订。