diff --git a/src/flake8/plugins/pyflakes.py b/src/flake8/plugins/pyflakes.py
index c82bf8e9..9b4fa6aa 100644
--- a/src/flake8/plugins/pyflakes.py
+++ b/src/flake8/plugins/pyflakes.py
@@ -67,17 +67,35 @@
 }
 
 
-class FlakesChecker(pyflakes.checker.Checker):
+class FlakesChecker:
     """Subclass the Pyflakes checker to conform with the flake8 API."""
 
-    with_doctest = False
+    _with_doctest = False
+    _builtins = None
 
     def __init__(self, tree: ast.AST, filename: str) -> None:
         """Initialize the PyFlakes plugin with an AST tree and filename."""
-        super().__init__(
-            tree, filename=filename, withDoctest=self.with_doctest,
+        self._checker = pyflakes.checker.Checker(
+            tree,
+            filename=filename,
+            builtins=self._builtins,
+            withDoctest=self._with_doctest,
         )
 
+    def run(self) -> Generator[tuple[int, int, str, type[Any]]]:
+        """Run the plugin."""
+        for message in self._checker.messages:
+            col = getattr(message, "col", 0)
+            yield (
+                message.lineno,
+                col,
+                "{} {}".format(
+                    FLAKE8_PYFLAKES_CODES.get(type(message).__name__, "F999"),
+                    message.message % message.message_args,
+                ),
+                message.__class__,
+            )
+
     @classmethod
     def add_options(cls, parser: OptionManager) -> None:
         """Register options for PyFlakes on the Flake8 OptionManager."""
@@ -98,20 +116,5 @@ def add_options(cls, parser: OptionManager) -> None:
     @classmethod
     def parse_options(cls, options: argparse.Namespace) -> None:
         """Parse option values from Flake8's OptionManager."""
-        if options.builtins:
-            cls.builtIns = cls.builtIns.union(options.builtins)
-        cls.with_doctest = options.doctests
-
-    def run(self) -> Generator[tuple[int, int, str, type[Any]]]:
-        """Run the plugin."""
-        for message in self.messages:
-            col = getattr(message, "col", 0)
-            yield (
-                message.lineno,
-                col,
-                "{} {}".format(
-                    FLAKE8_PYFLAKES_CODES.get(type(message).__name__, "F999"),
-                    message.message % message.message_args,
-                ),
-                message.__class__,
-            )
+        cls._builtins = options.builtins
+        cls._with_doctest = options.doctests
diff --git a/tests/integration/plugins/test_pyflakes.py b/tests/integration/plugins/test_pyflakes.py
new file mode 100644
index 00000000..5dd6325c
--- /dev/null
+++ b/tests/integration/plugins/test_pyflakes.py
@@ -0,0 +1,19 @@
+from __future__ import annotations
+
+from flake8.main.cli import main
+
+
+def test_pyflakes_builtins(tmpdir, capsys):
+    t_py = tmpdir.join('t.py')
+    t_py.write('print(b)\n')
+
+    expected = "t.py:1:7: F821 undefined name 'b'\n"
+    with tmpdir.as_cwd():
+        ret = main(('t.py',))
+    out, err = capsys.readouterr()
+    assert (ret, out, err) == (1, expected, '')
+
+    with tmpdir.as_cwd():
+        ret = main(('t.py', '--builtins', 'b'))
+    out, err = capsys.readouterr()
+    assert (ret, out, err) == (0, '', '')