Nous réfléchissons au futur. Tu ________ réfléchis aussi?

Hi Szilard,

I think that what you are seeing in the short sentence above is the usage of the verb form

réfléchir à (qch) so "We think (or consider) to the future. Do you do (this) also?"

Where "Y" is as you suggest "à + it (the concept/sense or feeling) / something"

So I think that you are broadly understanding the usage réfléchir à (qch).

Bonne continuation,

Jim

Jim's right: y replaces au futur, which, as you point out, is à + le futur.