I think the largest manufacturer of (real) post-war Czechoslovakia was not Letov, or Avia, but Aero. Even if I will not count licensed production of MiGs - Their own 3500 L-29 DelfÃÂn and around 2800 L-39 Albatros is quite significant production. Letov had a considerable proportion on the production of them, but it was under the leadership of Aero.