Thread: Problems in linked lists

Hello guys,
I got a problem in my code which is suposed to work as a linked lists of airplanes and each node in the list(Airplane) has another list beneath it as a nother linked list of passengers, but the problem that the linked list of passengers for each airplane is each time in implemntation is lost

***Airplane class***

public class Airplane {
	public String name;
	public int number;
	public double time; 
	public String caName;
 
	public Airplane next;
	public Passenger refPass;
 
 
    public Airplane(String nm, int num, double tm, String cName) {
    	name=nm;
    	number=num;
    	time=tm;
    	caName=cName;
    	next=null;
    	refPass=null;
    }
    public Airplane(String nm, int num, double tm, String cName, Airplane n, Passenger refP) {
    	name=nm;
    	number=num;
    	time=tm;
    	caName=cName;
    	next=n;
    	refPass=refP;
    } 
 
 
 
}

***Passengers Calss***

public class Passenger {
	public String frName;
	public String laName;
	public int id;
	public int seatNumber;
	public int lagNumber;
 
	public Passenger next;
 
    public Passenger(String fNM, String laNM, int d, int sNum, int lgNum ) {
    frName=fNM;
     laName=laNM;
	 id=d;
	 seatNumber=sNum;
	 lagNumber=lgNum;
	 next=null;
 
 
    }
 
    public Passenger(String fNM, String laNM, int d, int sNum, int lgNum, Passenger n ) {
    frName=fNM;
     laName=laNM;
	 id=d;
	 seatNumber=sNum;
	 lagNumber=lgNum;
	 next=n;
 
 
    }
 
 
 
 
}

***List and implemntation methods Class***

import java.util.Scanner;
 
 
public class List {
 
	public Airplane head, tail;
	public Passenger tmpPass;
 
	Scanner kk=new Scanner(System.in);
 
    public List() {
    		head=tail=null;
    		tmpPass=null;
    }
 
    public void addToTail(String nm, int num, double tm, String cName)/// Insertion for airplanes and flights.
    {
    	// A pointer from an Airplane node to point and the first passenger node.
    	if (head==null)
    	{
    		head=tail=new Airplane(nm,  num,  tm,  cName);
    		tmpPass=tail.refPass;// Assigning the pointer to the passenger list pointer.
    		String firstName;
	 String lastName;
	 int iD;
	 int seatNumber;
	 int lagNumber;
 
    	String op;
    	do{
 
 
    		System.out.println("***Passenger Info***");
    		System.out.print("First Name:");
    		firstName=kk.next();
    		System.out.print("Last Name:");	
    		lastName=kk.next();
    		System.out.print("ID:");
    		iD=kk.nextInt();
    		System.out.print("Seat Number:");
    		seatNumber=kk.nextInt();
    		System.out.print("Luggage Number:");
    		lagNumber=kk.nextInt();
    		tmpPass=new Passenger(firstName, lastName, iD, seatNumber, lagNumber, tmpPass);// Creating a passenger node.
 
 
    		System.out.println("Do you want to add more passenger[Yes/No]");
    		op=kk.next();
    	}while(!op.equalsIgnoreCase("No"));
    	}
 
    	else
    	{
    		tail.next=new Airplane(nm,  num,  tm,  cName);
         	tail = tail.next;
         	tmpPass=tail.refPass;// Assigning the pointer to the passenger list pointer.
         	String firstName;
	 String lastName;
	 int iD;
	 int seatNumber;
	 int lagNumber;
 
    	String op;
    	do{
 
 
    		System.out.println("***Passenger Info***");
    		System.out.print("First Name:");
    		firstName=kk.next();
    		System.out.print("Last Name:");	
    		lastName=kk.next();
    		System.out.print("ID:");
    		iD=kk.nextInt();
    		System.out.print("Seat Number:");
    		seatNumber=kk.nextInt();
    		System.out.print("Luggage Number:");
    		lagNumber=kk.nextInt();
    		tmpPass=new Passenger(firstName, lastName, iD, seatNumber, lagNumber, tmpPass);// Creating a passenger node.
 
 
    		System.out.println("Do you want to add more passenger[Yes/No]");
    		op=kk.next();
    	}while(!op.equalsIgnoreCase("No"));
    	}		
    }
 
 
 
    public boolean searchFlight(int nm)
    {
 
    	Airplane tmp;
 
    	for(tmp=head; tmp!=null &&tmp.number!=nm; tmp=tmp.next);
    	printFlighrSInfo(tmp);
 
 
 
 
    		return tmp!=null;
    }
 
     public void printFlighrSInfo(Airplane tmp)
    {
    	        System.out.println("Found");
            	System.out.println("Flight Info");
            	System.out.println("Airplane Type:"+tmp.name);
 
	 			System.out.println("Flight Number:"+tmp.number);
 
	 			System.out.println("Time:"+tmp.time);
 
	 			System.out.println("Captin Name:"+tmp.caName);
 
 
	 			int n=1;
	 				Passenger tmpPass;
	 			tmpPass=tmp.refPass;
 
 
 
	 		for(; tmpPass!=null; tmpPass=tmpPass.next)
	 		{
 
 
 
 
    		System.out.println("Passenger"+n+" Info");
    		System.out.println("First Name:"+tmpPass.frName);
    		System.out.println("Last Name:"+tmpPass.laName);
    		System.out.println("ID:"+tmpPass.id);
    		System.out.println("Seat Number:"+tmpPass.seatNumber);
    		System.out.println("Luggage Number:"+tmpPass.lagNumber);}	
 
 
    	}
 
    	public void printAll()
    	{
    		Airplane tmp;
    		Passenger tmp2;
    		for(tmp=head; tmp!=null; tmp=tmp.next)
    		{
    		for(tmp2=tmp.refPass; tmp2!=null; tmp2=tmp2.next)
    		{
    			System.out.println("Name"+tmp2.frName);
    		}	
    		}
    	}
 
}

***Main Class***

import java.util.Scanner;
 
public class Airport {
 
    public static void main(String[] args) {
        Scanner k=new Scanner(System.in);
        List listo=new List();
 
        int option;
 
     String name;
	 int number;
	 double time; 
	 String caName;
	 do{
	 	System.out.print("option:");
	 	option=k.nextInt();
	 	switch(option)
	 	{
	 		case 1:
	 			System.out.println("***Flight Info***");
	 			System.out.print("Airplane Type:");
	 			name=k.next();
	 			System.out.print("Flight Number:");
	 			number=k.nextInt();
	 			System.out.print("Time:");
	 			time=k.nextDouble();
	 			System.out.print("Captin Name:");
	 			caName=k.next();
	 			listo.addToTail(name, number, time, caName);
	 			break;
	 			case 2:
	 				System.out.print("Search Flight No:");
	 				number=k.nextInt();
	 				boolean b=listo.searchFlight(number);
	 				if(b==true)
	 				{
 
	 					listo.searchFlight(number);
 
 
	 					}
	 					else
	 						System.out.println("Not found");
	 			break;
	 			case 3:
	 				listo.printAll();
 
	 				break;
	 	}
 
	 }while(option!=10);
    }
 
 
}

Please help urgent

Tahnks