Бинарный поиск, ошибка: "Invalid operands to binary expression"

#include <iostream>
#include <sstream>
#include <vector>
#include <algorithm>
#include <string>
 
using namespace std;
 
struct Luggage {
    unsigned short int flight_number;
    std::string date_and_time;
    std::string surname;
    float weight;
    //Конструктор для Luggage
    Luggage(unsigned short int F, std::string D, std::string S, float W){
        flight_number=F;
        date_and_time=D;
        surname=S;
        weight=W;
    }
};
 
bool sort_function (Luggage i, Luggage j){
    return (i.flight_number<j.flight_number);
}
 
int main()
{
    vector<Luggage> luggage_base;
    //Итератор для поиска
    vector<Luggage>::iterator it;
    
    Luggage luggage1(526, "12 april 2015 14:45", "Ivanov", 12.5);
    Luggage luggage2(602, "16 february 2015 18:30", "Petrov", 17.2);
    Luggage luggage3(450, "17 march 2015 06:45", "Sidorov", 5.0);
    Luggage luggage4(575, "5 june 2015 15:00", "Pavlov", 10.6);
 
    luggage_base.push_back(luggage1);
    luggage_base.push_back(luggage2);
    luggage_base.push_back(luggage3);
    luggage_base.push_back(luggage4);
    
    //Сортировка по номеру рейса
    std::sort(luggage_base.begin(), luggage_base.end(), sort_function);
    
    cout << luggage_base[0].flight_number;
    cout << luggage_base[1].flight_number;
    cout << luggage_base[2].flight_number;
    cout << luggage_base[3].flight_number;
    
    //Бинарный поиск по номеру рейса
    it=lower_bound(luggage_base.begin(), luggage_base.end(), 575);
}

    bool operator<(const Luggage & rhs) const {
        return (this->flight_number < rhs.flight_number);
    }

int seach = 575;
    auto ptr = find_if(luggage_base.begin(), luggage_base.end(), [&seach](Luggage val)
    {
        return val.flight_number == seach;
    });