Untitled

string[] menu = new string[]
{
    "Book",
    "Exit"
};

Console.WriteLine("Menu");

for (int i = 0; i < menu.GetLength(0); i++)
{
    Console.WriteLine($"{i + 1}. {menu[i]}");
}

ConsoleKeyInfo keyInfo = Console.ReadKey();

switch (keyInfo.Key)
{
    case ConsoleKey.UpArrow: 
        break;
    case ConsoleKey.DownArrow: 
        break;
}

static void ShowSeats()
{
    string[,] aviaTickets = new string[6, 4]
    {
    { " [A1] ", " [A2] "," [A3] "," [A4] " },
    { " [B1] ", " [B2] "," [B3] "," [B4] " },
    { " [C1] ", " [C2] "," [C3] "," [C4] " },
    { " [D1] ", " [D2] "," [D3] "," [D4] " },
    { " [E1] ", " [E2] "," [E3] "," [E4] " },
    { " [F1] ", " [F2] "," [F3] "," [F4] " }
    };

    for (int i = 0; i < aviaTickets.GetLength(0); i++)
    {
        for (int j = 0; j < aviaTickets.GetLength(1); j++)
        {
            Console.Write(aviaTickets[i, j]);
        }
        Console.WriteLine();
    }
}