You defined Hotel class and Flight class correctly in their same named source file, but redefined them as inner class of the Reservation again. And you inner class Reservation in the Reservation class.

public class Reservation $\{$

private String customerName;

private Flight flight;

private Hotel room;

$//$ Non$-$argument constructor

public Reservation$()\{\}$

public class Flight $\{$

private String airlines;

private int flightNumber;

private double flightFare;

$//$ Non$-$argument constructor

public Flight$()\{\}$

$//$ Full constructor

public Flight$($String airlines, int flightNumber, double flightFare$)\{$

this.airlines $=$ airlines;

this.flightNumber $=$ flightNumber;

this.flightFare $=$ flightFare;

$\}$

$//$ Set and get methods for airlines

public void setAirlines$($String airlines$)\{$

this.airlines $=$ airlines;

$\}$

public String getAirlines$()\{$

return airlines;

$\}$

$//$ Set and get methods for flightNumber

public void setFlightNumber$($int flightNumber$)\{$

this.flightNumber $=$ flightNumber;

$\}$

public int getFlightNumber$()\{$

return flightNumber;

$\}$

$//$ Set and get methods for flightFare

public void setFlightFare$($double flightFare$)\{$

this.flightFare $=$ flightFare;

$\}$

public double getFlightFare$()\{$

return flightFare;

$\}$

@Override

public String toString$()\{$

return "Airlines: $"+$ airlines $+",$ Flight Number: $"+$ flightNumber $+",$ Flight Fare: $$"+$ flightFare;

$\}$

$\}$