diff --git a/1ano/2semestre/poo/src/aula11/ex4/Company.java b/1ano/2semestre/poo/src/aula11/ex4/Company.java
new file mode 100644
index 0000000..83b975e
--- /dev/null
+++ b/1ano/2semestre/poo/src/aula11/ex4/Company.java
@@ -0,0 +1,19 @@
+package aula11.ex4;
+
+import java.util.LinkedList;
+import java.util.Objects;
+
+public record Company(String code, String name, LinkedList<Flight> flights) {
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof Company company)) return false;
+        return Objects.equals(code, company.code) && Objects.equals(name, company.name) && Objects.equals(flights, company.flights);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(code, name, flights);
+    }
+}
diff --git a/1ano/2semestre/poo/src/aula11/ex4/Flight.java b/1ano/2semestre/poo/src/aula11/ex4/Flight.java
new file mode 100644
index 0000000..c52bec8
--- /dev/null
+++ b/1ano/2semestre/poo/src/aula11/ex4/Flight.java
@@ -0,0 +1,17 @@
+package aula11.ex4;
+
+import java.util.Objects;
+
+public record Flight(String code, String origin, Time departure, Time delay, Company company) {
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof Flight flight)) return false;
+        return Objects.equals(code, flight.code) && Objects.equals(origin, flight.origin) && Objects.equals(departure, flight.departure) && Objects.equals(delay, flight.delay);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(code, origin, departure, delay);
+    }
+}
diff --git a/1ano/2semestre/poo/src/aula11/ex4/FlightManager.java b/1ano/2semestre/poo/src/aula11/ex4/FlightManager.java
new file mode 100644
index 0000000..9496d81
--- /dev/null
+++ b/1ano/2semestre/poo/src/aula11/ex4/FlightManager.java
@@ -0,0 +1,138 @@
+package aula11.ex4;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.*;
+import java.io.*;
+import java.util.stream.Collectors;
+
+public class FlightManager {
+    private final LinkedList<Company> companies = new LinkedList<>();
+    private final LinkedList<Flight> flights = new LinkedList<>();
+    private String table;
+    private String delaysTable;
+    private String flightsNTable;
+
+    public void loadCompanies(String filename) {
+        Scanner input;
+        try {
+            input = new Scanner(new FileReader(filename));
+            input.nextLine();
+        } catch (FileNotFoundException e) {
+            throw new RuntimeException(e);
+        }
+        while(input.hasNext()){
+            String line = input.nextLine();
+            String[] fields = line.split("\t");
+            if(fields.length != 2)
+                throw new RuntimeException("Invalid file format");
+            this.companies.add(new Company(fields[0], fields[1], new LinkedList<>()));
+        }
+    }
+
+    public void loadFlights(String filename) {
+        Scanner input;
+        try {
+            input = new Scanner(new FileReader(filename));
+            input.nextLine();
+        } catch (FileNotFoundException e) {
+            throw new RuntimeException(e);
+        }
+        while (input.hasNext()) {
+            String line = input.nextLine();
+            String[] fields = line.split("\t");
+            if (fields.length != 3 && fields.length != 4)
+                throw new RuntimeException("Invalid file format");
+            String[] timeStr = fields[0].split(":");
+            Time time = new Time(Integer.parseInt(timeStr[0]), Integer.parseInt(timeStr[1]));
+            String code = fields[1];
+            Company company = this.companies.stream().filter(c -> c.code().equals(code.substring(0, 2))).findFirst().orElse(null);
+            String origin = fields[2];
+            String[] delayStr;
+            try {
+                delayStr = fields[3].split(":");
+            } catch (IndexOutOfBoundsException e) {
+                delayStr = new String[]{"0", "0"};
+            }
+            Time delay = new Time(Integer.parseInt(delayStr[0]), Integer.parseInt(delayStr[1]));
+            Flight flight = new Flight(code, origin, time, delay, company);
+            this.flights.add(flight);
+            Objects.requireNonNull(company).flights().add(flight);
+        }
+    }
+
+    public void buildTable() {
+        StringBuilder table = new StringBuilder().append("Depart.   Flight    Company                  Origin                   Delay   Obs\n");
+        for (Flight flight : flights)
+            table.append(String.format("%-10s%-10s%-25s%-25s%-8s%s%n", flight.departure(), flight.code(), flight.company().name(), flight.origin(), flight.delay(), flight.delay().isZero() ? "" : "New departure: " + flight.departure().addTime(flight.delay())));
+        this.table = table.toString();
+    }
+
+    public String getTable() {
+        return table;
+    }
+
+    public void buildDelaysTable() {
+        StringBuilder table = new StringBuilder().append("Company                  Avg. Delay\n");
+        LinkedHashMap<String, Integer> delays = new LinkedHashMap<>();
+        for (Company company : companies) {
+            Time totalTime = new Time(0, 0);
+            int nDelays = 0;
+            for (Flight flight : company.flights()) {
+                if (!flight.delay().isZero()) {
+                    totalTime.addTime(flight.delay());
+                    nDelays++;
+                }
+            }
+            if (nDelays > 0)
+                delays.put(company.name(), Time.timeToMinsInt(totalTime) / nDelays);
+        }
+        delays = (LinkedHashMap<String, Integer>) sortByValue(delays);
+        for (String compName : delays.keySet())
+            table.append(String.format("%-25s%s%n", compName, Time.minsIntToTime(delays.get(compName))));
+        this.delaysTable = table.toString();
+    }
+
+    public String getDelaysTable() {
+        return delaysTable;
+    }
+
+    public void buildFlightsNTable() {
+        StringBuilder table = new StringBuilder().append("Origin                   n Flights\n");
+        LinkedHashMap<String, Integer> flightsFromOrigin = new LinkedHashMap<>();
+        for (Flight flight : flights)
+            flightsFromOrigin.put(flight.origin(), flightsFromOrigin.getOrDefault(flight.origin(), 0) + 1);
+        flightsFromOrigin = (LinkedHashMap<String, Integer>) sortByValue(flightsFromOrigin);
+        for (String origin : flightsFromOrigin.keySet())
+            table.append(String.format("%-25s%s%n", origin, flightsFromOrigin.get(origin)));
+        this.flightsNTable = table.toString();
+    }
+
+    public String getFlightsNTable() {
+        return flightsNTable;
+    }
+
+    public void storeTable(String filename) {
+        Path path = Path.of(filename);
+        try {
+            Files.writeString(path, getTable());
+        } catch (IOException e) {
+            try {
+                Files.createFile(path);
+                storeTable(filename);
+            } catch (IOException ex) {
+                throw new RuntimeException(ex);
+            }
+        }
+    }
+
+    private static Map<String, Integer> sortByValue(Map<String, Integer> unsortMap) {
+        List<Map.Entry<String, Integer>> list = new LinkedList<>(unsortMap.entrySet());
+
+        // Sorting the list based on values
+        list.sort((o1, o2) -> o2.getValue().compareTo(o1.getValue()) == 0
+                ? o2.getKey().compareTo(o1.getKey())
+                : o2.getValue().compareTo(o1.getValue()));
+        return list.stream().collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (a, b) -> b, LinkedHashMap::new));
+    }
+}
diff --git a/1ano/2semestre/poo/src/aula11/ex4/Main.java b/1ano/2semestre/poo/src/aula11/ex4/Main.java
new file mode 100644
index 0000000..46c216f
--- /dev/null
+++ b/1ano/2semestre/poo/src/aula11/ex4/Main.java
@@ -0,0 +1,21 @@
+package aula11.ex4;
+
+public class Main {
+    public static void main(String[] args) {
+        FlightManager fm = new FlightManager();
+
+        fm.loadCompanies("datafiles/aula11/ex4/companhias.txt");
+        fm.loadFlights("datafiles/aula11/ex4/voos.txt");
+
+        fm.buildTable();
+        System.out.println(fm.getTable());
+
+        fm.buildDelaysTable();
+        System.out.println(fm.getDelaysTable());
+
+        fm.buildFlightsNTable();
+        System.out.println(fm.getFlightsNTable());
+
+        fm.storeTable("datafiles/aula11/ex4/Infopublico.txt");
+    }
+}
diff --git a/1ano/2semestre/poo/src/aula11/ex4/Time.java b/1ano/2semestre/poo/src/aula11/ex4/Time.java
new file mode 100644
index 0000000..e9ee148
--- /dev/null
+++ b/1ano/2semestre/poo/src/aula11/ex4/Time.java
@@ -0,0 +1,52 @@
+package aula11.ex4;
+
+public class Time {
+    private int hour;
+    private int minute;
+
+    public Time(int hour, int minute) {
+        if (hour < 0 || hour > 23 || minute < 0 || minute > 59)
+            throw new IllegalArgumentException("Invalid time");
+        this.hour = hour;
+        this.minute = minute;
+    }
+
+    public Time addTime(Time time) {
+        int newHour = hour + time.hour();
+        int newMinute = minute + time.minute();
+        if (newMinute >= 60) {
+            newHour++;
+            newMinute -= 60;
+        }
+        if (newHour >= 24)
+            newHour -= 24;
+        this.hour = newHour;
+        this.minute = newMinute;
+        return new Time(newHour, newMinute);
+    }
+
+    public boolean isZero() {
+        return hour == 0 && minute == 0;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("%02d:%02d", hour, minute);
+    }
+
+    public static int timeToMinsInt(Time time) {
+        return time.hour() * 60 + time.minute();
+    }
+
+    public static Time minsIntToTime(int mins) {
+        return new Time(mins/60, mins%60);
+    }
+
+    public int hour() {
+        return hour;
+    }
+
+    public int minute() {
+        return minute;
+    }
+}