private void addNewCustomerMenu()
{
Console.WriteLine("Register New customer.");
Console.WriteLine("======================");
Console.Write("Enter Customer Name: ");
string name = Console.ReadLine();
Console.Write("Enter Customer Flight Number: ");
int flightId = Convert.ToInt32(Console.ReadLine());
Customer customer = new Customer(name, flightId);
customerController.addNewCustomer(customer);
Console.WriteLine();
mainMenu();
}