As long as the water flow is fast enough, any small bubbles will get flushed out. This is a function of the siphon size vs. pump flow. When I use 2 1" siphons with my 750 gph
pump <thinking maybe 2 is better due to redundancy>, I got air accumulation. Removing 1 of the 2 siphon cures the problem.
If you have a wier type overflow (eg CPR), then using a PH to evacuate air is recommended, as the flow in the wier is too slow to clear bubbles.
There are ways to quieten the overflow. A Durso attachment is one, as is a fully submerged standpipe system, like this:
BeanAnimal's Bar and Grill - Silent and Fail-Safe Overflow System