Don't know if you can get them in Canada, but we use Playtex Disposables as well. The ones with the drop-in flexible liners. You can squeeze out the air before baby eats and the lines actually collapse as they drink the formula out of them. Can't say no air gets into baby, but less than others in my humble opinion.
We tried the Avent bottles with our LO and she had terrible gas. We were very diligent in burping her, but just couldn't get anything out. It was so bad that we tried the Playtex system and within 2 days had replaced all of our Avent bottles with the Playtex bottles/liners. Our LO still gets some air, but nothing like what she was getting with the Avent bottles.
Having said this, all babies are different - this is just what works for us!
