probably the last on

src/Airplane.java

 import java.util.ArrayList;
 
+/**
+ * airplane of the flight
+ */
 public class Airplane {
 
     private String type;
     private ArrayList<Seat> seats;
     private ArrayList<Seat> freeSeats;
 
+    /**
+     * constructs an airplane
+     *
+     * @param seats
+     * @param type
+     */
     public Airplane(ArrayList<Seat> seats, String type) {
         this.seats = seats;
         this.freeSeats = seats;
         this.type = type;
     }
 
+    /**
+     * returns free seats
+     *
+     * @return
+     */
     public ArrayList<Seat> getFreeSeats() {
         return freeSeats;
     }
 
+    /**
+     * returns all of seats
+     *
+     * @return
+     */
     public ArrayList<Seat> getSeats() {
         return seats;
     }
 
+    /**
+     * returns the type of seat
+     *
+     * @return
+     */
     public String getType() {
         return type;
     }
 
+    /**
+     * reserves a seat for a passenger on this airplane
+     *
+     * @param seat
+     * @param passenger
+     */
     public void reserve(Seat seat, Passenger passenger) {
         for (Seat s : seats
         ) {

src/Flight.java

 import java.util.ArrayList;
 
+/**
+ * an available flight
+ */
 public class Flight {
 
     private Airplane airplane;
@@ -10,6 +13,17 @@ public class Flight {
     private int No;
     private int date;
 
+    /**
+     * constructs a flight
+     *
+     * @param airplane
+     * @param company
+     * @param destination
+     * @param origin
+     * @param type
+     * @param No
+     * @param date
+     */
     public Flight(Airplane airplane, String company, String destination, String origin, String type, int No, int date) {
         this.airplane = airplane;
         this.company = company;
@@ -20,42 +34,93 @@ public class Flight {
         this.date = date;
     }
 
+    /**
+     * returns type of this flight
+     *
+     * @return
+     */
     public String getType() {
         return type;
     }
 
+    /**
+     * returns number of this flight
+     *
+     * @return
+     */
     public int getNo() {
         return No;
     }
 
+    /**
+     * returns airplane of this flight
+     *
+     * @return
+     */
     public Airplane getAirplane() {
         return airplane;
     }
 
+    /**
+     * returns company of this flight
+     *
+     * @return
+     */
     public String getCompany() {
         return company;
     }
 
+    /**
+     * returns destination of this flight
+     *
+     * @return
+     */
     public String getDestination() {
         return destination;
     }
 
+    /**
+     * returns origin of this flight
+     *
+     * @return
+     */
     public String getOrigin() {
         return origin;
     }
 
+    /**
+     * returns date of this flight
+     *
+     * @return
+     */
     public int getDate() {
         return date;
     }
 
+    /**
+     * returns free seats on this flight
+     *
+     * @return
+     */
     public ArrayList<Seat> getFreeSeats() {
         return this.airplane.getFreeSeats();
     }
 
+    /**
+     * returns total seats of this flight
+     *
+     * @return
+     */
     public ArrayList<Seat> getSeats() {
         return this.airplane.getSeats();
     }
 
+    /**
+     * reserves a seat for a passenger
+     *
+     * @param seat
+     * @param passenger
+     */
     public void reserve(Seat seat, Passenger passenger) {
         this.airplane.reserve(seat, passenger);
     }

src/Passenger.java

 import java.util.ArrayList;
 
+/**
+ * passenger of the flight
+ */
 public class Passenger {
 
     private String name;
@@ -7,17 +10,37 @@ public class Passenger {
     int ID;
     ArrayList<Ticket> tickets = null;
 
+    /**
+     * constructs a passenger
+     *
+     * @param name
+     * @param lastName
+     * @param ID
+     */
     public Passenger(String name, String lastName, int ID) {
         this.name = name;
         this.lastName = lastName;
         this.ID = ID;
     }
 
+    /**
+     * reserves a ticket for this passenger
+     *
+     * @param flight
+     * @param seat
+     * @param hasFood
+     * @param weight
+     */
     public void reserve(Flight flight, Seat seat, Boolean hasFood, int weight) {
         Ticket ticket = new Ticket(seat.getNo(), flight.getNo(), weight, hasFood);
         this.tickets.add(ticket);
     }
 
+    /**
+     * returns passenger's tickets
+     *
+     * @return
+     */
     public ArrayList<Ticket> getTickets() {
         return tickets;
     }

src/Seat.java

+/**
+ * seat of the airplane
+ */
 public class Seat {
 
     private int No;
     private String type;
     private Passenger passenger;
 
-    public Seat(int No, String type){
+    /**
+     * constructs a seat
+     *
+     * @param No
+     * @param type
+     */
+    public Seat(int No, String type) {
         this.No = No;
         this.type = type;
     }
 
+    /**
+     * returns seats number
+     *
+     * @return
+     */
     public int getNo() {
         return No;
     }
 
+    /**
+     * return seats type
+     *
+     * @return
+     */
     public String getType() {
         return type;
     }
 
+    /**
+     * relates a passenger to this seat
+     *
+     * @param passenger
+     */
     public void setPassenger(Passenger passenger) {
         this.passenger = passenger;
     }
 
+    /**
+     * returns passenger who reserved this seat
+     *
+     * @return
+     */
     public Passenger getPassenger() {
         return passenger;
     }

src/SystemManagement.java

 import java.util.ArrayList;
 
+/**
+ * the manager of all flights
+ */
 public class SystemManagement {
 
     private ArrayList<Flight> flights;
 
+    /**
+     * constructs a system management
+     *
+     * @param flights
+     */
     public SystemManagement(ArrayList<Flight> flights) {
         this.flights = flights;
     }
 
+    /**
+     * adds a flight to the flight list
+     *
+     * @param flight
+     */
     public void addFlight(Flight flight) {
         this.flights.add(flight);
     }
 
+    /**
+     * removes a flight from the flight list
+     *
+     * @param flight
+     */
     public void removeFlight(Flight flight) {
         this.flights.remove(flight);
     }
 
+    /**
+     * returns all of the flights
+     *
+     * @return
+     */
     public ArrayList<Flight> getFlights() {
         return flights;
     }
 
+    /**
+     * reserves a seat from a flight for a passenger
+     *
+     * @param flight
+     * @param seat
+     * @param passenger
+     */
     public void reserve(Flight flight, Seat seat, Passenger passenger) {
         for (Flight f : flights
         ) {

src/Ticket.java

+/**
+ * reservation ticket
+ */
 public class Ticket {
 
     private int SeatNo;
@@ -5,25 +8,53 @@ public class Ticket {
     private int baggageWeight;
     private Boolean foodStatus;
 
-    public Ticket(int seatNo, int flightNo, int baggageWeight, Boolean foodStatus){
+    /**
+     * constructs a ticket
+     *
+     * @param seatNo
+     * @param flightNo
+     * @param baggageWeight
+     * @param foodStatus
+     */
+    public Ticket(int seatNo, int flightNo, int baggageWeight, Boolean foodStatus) {
         this.SeatNo = seatNo;
         this.flightNo = flightNo;
         this.baggageWeight = baggageWeight;
         this.foodStatus = foodStatus;
     }
 
+    /**
+     * returns the food status
+     *
+     * @return
+     */
     public Boolean getFoodStatus() {
         return foodStatus;
     }
 
+    /**
+     * returns the baggage weight
+     *
+     * @return
+     */
     public int getBaggageWeight() {
         return baggageWeight;
     }
 
+    /**
+     * returns the flight number
+     *
+     * @return
+     */
     public int getFlightNo() {
         return flightNo;
     }
 
+    /**
+     * returns the seat nomber
+     *
+     * @return
+     */
     public int getSeatNo() {
         return SeatNo;
     }