User blog comment:Mobo85/Walt Disney Studios Cancels "Phineas and Ferb" Feature Film/@comment-4241330-20130911122537/@comment-3477287-20130912224211

Actually, a large number of work use their episodes as pilots for spinoffs. For example, "Crash Nebula" is episode 69 of Fairly Odd Parents but is a (unsuccessful) pilot for a planned Crash Nebula spinoff. So even if the episode has the "Phineas and Ferb" banner and an episode number, it could still be a spinoff pilot.