What game and edition?
1. I'm not sure the bats could fly in sync well enough to be able to coordinate pulling a glider.
2. I don't think dire bats have enough acceleration to get one off the ground, but once airborne, they might be able to keep it aloft.
3. you would probably want to detach and glide to a landing, instead of having the bats land with it in tow.
4. the Weight of the glider and cargo would need to be limited to keep from fatiguing the bat, they aren't built for hauling like a horse is. (Perhaps some sort of levitate on the glider)
5. While it's a cool image..... Just use a flying carpet, or cloak of the bat, etc.
Ok so hear me out and tell me all the ways this would not work.
Can a dire bat or two of them pull a glider with a medium sized PC as a sort of flying chariot?
Yes. Who cares about the rules even if they say no, that sounds awesome.