CREATE TABLE table_484 ("Season #" FLOAT, "Series #" FLOAT, "Title" TEXT, "Canadian airdate" TEXT, "U.S. airdate" TEXT, "Production code" FLOAT)

What is the maximum season # with a u.s. air date is may 1, 2009
SELECT MAX("Season #") FROM table_484 WHERE "U.S. airdate" = 'May 1, 2009'
SELECT MAX("Season #") FROM "table_484" WHERE "U.S. airdate" = 'May 1, 2009'