diff --git a/src/location/Airports.zig b/src/location/Airports.zig
index 99e3092..2f9db6f 100644
--- a/src/location/Airports.zig
+++ b/src/location/Airports.zig
@@ -9,7 +9,7 @@ pub const Airport = struct {
 
 const Airports = @This();
 
-allocator: std.mem.Allocator,
+arena: std.heap.ArenaAllocator,
 airports: std.StringHashMap(Airport),
 
 pub fn init(allocator: std.mem.Allocator) !Airports {
@@ -18,31 +18,28 @@ pub fn init(allocator: std.mem.Allocator) !Airports {
 }
 
 pub fn initFromData(allocator: std.mem.Allocator, csv_data: []const u8) !Airports {
-    var airports = std.StringHashMap(Airport).init(allocator);
+    var arena = std.heap.ArenaAllocator.init(allocator);
+    const alloc = arena.allocator();
+    var airports = std.StringHashMap(Airport).init(alloc);
 
     var lines = std.mem.splitScalar(u8, csv_data, '\n');
     while (lines.next()) |line| {
         if (line.len == 0) continue;
 
-        const airport = parseAirportLine(allocator, line) catch continue;
-        if (airport.iata.len == 3) {
+        const airport = parseAirportLine(alloc, line) catch continue;
+        if (airport.iata.len == 3 and airports.get(airport.iata) == null) {
             try airports.put(airport.iata, airport);
         }
     }
 
     return Airports{
-        .allocator = allocator,
+        .arena = arena,
         .airports = airports,
     };
 }
 
 pub fn deinit(self: *Airports) void {
-    var it = self.airports.iterator();
-    while (it.next()) |entry| {
-        self.allocator.free(entry.key_ptr.*);
-        self.allocator.free(entry.value_ptr.name);
-    }
-    self.airports.deinit();
+    self.arena.deinit();
 }
 
 pub fn lookup(self: *Airports, iata_code: []const u8) ?Airport {