S45 may refer to:
== Aviation == Blériot-SPAD S.45, a French biplane airliner SABCA S-45bis, a Belgian bomber Short S.45, a British biplane trainer Short S.45 Seaford, a British flying boat Sikorsky S-45, a proposed American flying boat Siletz Bay State Airport, in Lincoln County, Oregon, United States
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).