Не работает метод IComparable для первого списка - C#

using System;
using System.Collections.Generic;
using System.Linq;
 
class Program
{
    class AirplanesProperties : IComparable<AirplanesProperties>
    {
        public int Number { get; set; }
        public int ArrivalTime { get; set; }
        public string City { get; set; }
        public string Airline { get; set; }
        public int Terminal { get; set; }
        public int ShippingFlight { get; set; }
        public int Bgate { get; set; }
 
        public AirplanesProperties() { }
        public AirplanesProperties(int number, int arrivalTime)
        {
            Number = number;
            ArrivalTime = arrivalTime;
        }
 
        public int CompareTo(AirplanesProperties obj)
        {
            if (ArrivalTime > obj.ArrivalTime)
                return 1;
            else if (ArrivalTime < obj.ArrivalTime)
                return -1;
 
            return 0;
        }
 
        public override string ToString()
        {
            return String.Format(" {1}\tnumber: {0:C}\tarrivalTime: ", ArrivalTime, Number);
        }
    }
 
    #region ArrivalTime1
    private static void Arrivaltime1()
    {
        int x, y, z, k;
        Console.WriteLine("arrivalTime1");
        x = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("arrivalTime2");
        y = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("arrivalTime3");
        z = Convert.ToInt32(Console.ReadLine());
        Console.WriteLine("arrivalTime4");
        k = Convert.ToInt32(Console.ReadLine());
 
        List<AirplanesProperties> fligths = new List<AirplanesProperties>()
            {
                new AirplanesProperties { Number = 1, ArrivalTime = x, },
                new AirplanesProperties { Number = 2, ArrivalTime = y, },
                new AirplanesProperties { Number = 3, ArrivalTime = z, },
                new AirplanesProperties { Number = 4, ArrivalTime = k, }
            };
        fligths.Sort();
        foreach (var item in fligths)
            Console.WriteLine(item);
    }
    #endregion
 
    #region Airline
    private static void Airline()
    {
        List<AirplanesProperties> fligth = new List<AirplanesProperties>()
        {
            new AirplanesProperties { Number = 1, City = "kiyev", Airline = "PAU", Terminal = 1, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 },
            new AirplanesProperties { Number = 2, City = "kiyev", Airline = "PAU", Terminal = 1, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 },
            new AirplanesProperties { Number = 3, City = "Odessa", Airline = "MAU", Terminal = 3, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 },
            new AirplanesProperties { Number = 4, City = "Odessa", Airline = "MAU", Terminal = 5, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 },
            new AirplanesProperties { Number = 4, City = "Odessa", Airline = "RAU", Terminal = 5, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 },
            new AirplanesProperties { Number = 5, City = "Odessa", Airline = "RAU", Terminal = 5, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 }
        };
        int n = Convert.ToInt32(Console.ReadLine());
        var filterFlight = fligth.Where(x => x.Number != n);
        foreach (var x in filterFlight)
        {
            Console.WriteLine(x.Airline + x.ArrivalTime + x.Bgate + x.City + x.Number);
        }
    }
    #endregion
 
    #region gate
    private static void gate()
    {
        List<AirplanesProperties> fligth = new List<AirplanesProperties>()
        {
            new AirplanesProperties { Number = 1, City = "kiyev", Airline = "PAU", Terminal = 1, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 },
            new AirplanesProperties { Number = 1, City = "kiyev", Airline = "PAU", Terminal = 1, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 },
            new AirplanesProperties { Number = 1, City = "Odessa", Airline = "MAU", Terminal = 3, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 },
            new AirplanesProperties { Number = 1, City = "Odessa", Airline = "MAU", Terminal = 5, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 },
            new AirplanesProperties { Number = 1, City = "Odessa", Airline = "RAU", Terminal = 5, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 },
            new AirplanesProperties { Number = 1, City = "Odessa", Airline = "MAU", Terminal = 5, ArrivalTime = 0, ShippingFlight = 0, Bgate = 1 }
        };
        string z = Console.ReadLine();
        var result = fligth.Where(x => x.Airline == z);
        foreach (var x in result)
        {
            Console.WriteLine(x.Airline + x.ArrivalTime + x.Bgate + x.City + x.Number);
        }
    }
    #endregion
 
    static void Main()
    {
        Console.WriteLine(@"Please,  type the number:
            1. arrivalTime1
            2. udalenie elementa massiva
            3. Poisk po aviakompanii
            ");
        int a = int.Parse(Console.ReadLine());
        switch (a)
        {
            case 1:
                Arrivaltime1();
                Console.WriteLine("");
                break;
            case 2:
 
                Airline();
                Console.WriteLine("");
                break;
            case 3:
                gate();
                Console.WriteLine("");
                break;
            default:
                Console.WriteLine("Exit");
                break;
        }
        Console.ReadKey();
    }
}