This heavy animal had trouble gaining altitude.
It flew fairly fast but relatively low, and landed on low, usually dry, vegetation from time to time.
It was hard to keep up with it, but one time it stayed a few seconds longer before taking off again; just long enough to take a few quick snaps.

We only see one species of Bumble Bee (B. Vosnesenskii) somewhat regularly at the Preserve.
Today I saw a much larger Bumble Bee, which I posted a moment ago, and presume is B. sonoran.

This giant was even much bigger.
Since the wings are worn it is likely what a lot of fur has also been lost, making it look different.
Given this, plus the huge size, could this be a queen ?
They are usually active earlier in the year, but it looks like she "has been around."