We're a week away from Titanfall (god forbid we post about it less than twice a day) and while we know it will get DLC (because of course it will and because they've said as much), post release plans haven't been explained.
Respawn's Vince Zampella tweeted that the game would not have a season pass, but community manager Abbie Heppe said this tweet was a mistake, clarifying that the game would not have an online pass (which EA finally stopped doing already). A season pass could still happen, but there are no announcements at this time. You should probably expect one anyway.
Heppe also gave a vague, "we'll see what happens after launch" response to the chances of a pilot versus pilot mode. Because when I see Titanfall, the first thing I think is, "Hmm, this would be better without the cool giant robots."