can you bring hydroflasks into six flags ?

Only if it Has Water

Six flags doesn't allow flasks or even water bottles. Any type of beverage you have to purchase inside the theme park.

U don't think so

You may be able to, they might or might not allow them through the bag check

Yes

Very discretely

U cant take anything that has to do with food into the park.

I think I remember seeing people with them but I'm not sure if it's the one they sell there or if they brought it from home