Tên Lửa Nước Dùng Bơm Xe Đạp

This makes a great rocket. Take note that it will fly VERY high (~100ft+) if you fill it with a lot of water and/or highly pressurize it. Be aware of your surroundings and take appropriate measures to keep yourself and others safe. 

Printing:
The cork and screw-on base are TPU (95A, I used Overture High-Speed TPU)
The fins can be just about anything that is not brittle. I used ASA, but PETG is probably as good or better option.

Assembly:
The cork should seat directly into the valve-stem connector on the bike pump. 
Slide the fins into the side of the screw-on adapter that has the threads closest to it, then screw that whole assembly onto a bottle. I used a 2 liter, but it should work fine with smaller (and maybe larger) bottles. I have tested neither.
I was able to use friction alone to get the fins to stay using TPU and ASA, but depending on what material you use, and print settings, you may need to glue them in.