Is Downward Fall of an Object Dependent on Its Mass (In a non-vacuum setup)

Recently, I was in an argument. This was the scenario:

Under normal conditions - with air present, if we drop 2 identical objects of different masses from a certain height, both would arrive together.

This was my argument.

Opposing this, my friends' said that since the masses of both objects are different, force due to air resistance applies unequal acceleration on both the objects.

I countered by saying that air resistance is a limiting force (like friction).

WE DO NOT KNOW WHO IS RIGHT.
WE MOST PROBABLY ARE NOT SCIENTIFICALLY ACCURATE HERE.

So, to put this to test,

I went 2 floors up, and dropped 2 water bottles - one half filled, another completely filled.

You may ask why didn't I keep one bottle completely empty - I did, and that just resulted in that bottle undergoing severe rotational motion, thus constantly changing it's shape facing air resistance, and it beat the whole purpose of having 2 identical objects.

The Results?

As you could see in the video, even though both bottles were slightly apart - almost one above the other, the distance between the two bottles remained constant - implying that they were both accelerating uniformly.