Yes, you can always use your Philips Avent Anti-colic bottle without the AirFree vent.
Specifically for younger babies (below 4 months)
We advise you to use the AirFree vent specifically for younger babies (below 4 months) with feeding issues. The AirFree vent allows your little one to manage air intake.
If your baby gets older and is able to drink from the bottle without any feeding issues, you can easily use the bottle without the AirFree vent.