CREATE TABLE table_24188 ("No in Series" FLOAT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original air date" TEXT, "Production code" FLOAT, "U.S. viewers  ( millions ) " TEXT)

How many original air dates were there for episodes with a production code of 4398016?
SELECT COUNT("Original air date") FROM table_24188 WHERE "Production code" = '4398016'
SELECT COUNT("Original air date") FROM "table_24188" WHERE "Production code" = '4398016'