Extinction Rebellion

I think she's a massive hypocrite.

You don't know what hypocrisy means. The Wikipedia definition will do:

Hypocrisy is the contrivance of a false appearance of virtue or goodness, while concealing real character or inclinations, especially with respect to religious and moral beliefs; hence, in a general sense, hypocrisy may involve dissimulation, pretense, or a sham.

It continues:

Hypocrisy is the practice of engaging in the same behavior or activity for which one criticizes another. In moral psychology, it is the failure to follow one's own expressed moral rules and principles.

Note that this part must be read in conjunction with the primary definition above; merely being inconsistent doesn't amount to hypocrisy. It requires that element of secrecy.

https://en.wikipedia.org/wiki/Hypocrisy

She doesn't hide that she flies and is therefore not a hypocrite about it. For the avoidance of doubt, I think she's wrong to fly while holding these beliefs, at best inconsistent, at worst self-contradictory, and she doesn't practise what she preaches, but she's not a hypocrite.

She's got a massive cheek getting involved in XR.

That may well be the case, but it's a different thing from hypocrisy.