private void btntracuu_Click(object sender, EventArgs e)
{
TraCuuChuyenBay f = new TraCuuChuyenBay();
f.Show();
}
private void traCứuChuyếnBayToolStripMenuItem_Click(object sender, EventArgs e)
{
TraCuuChuyenBay f = new TraCuuChuyenBay();
f.Show();
}