I had not aerated my lawn in over a decade and I thought I should really be doing this. The last time I did it was in the spring and I must admit I did get a bunch of weeds that season. I am not sure there was a direct correlation but I have not aerated since! I invited over Steve Mura from Barrett Lawn Care and he talked about all of the benefits.
Fall is the best time it turns out because your lawn is not competing with the weeds that are also starting to grow in the spring. If you are going to wait until spring do it early before the weeds are starting.
It is great for compacted soils, heavy thatch, and it really allows every lawn a chance to breath. This is a great time to introduce grass seed, and fertilizer. Bobby said the plug aeration is the best way to go. Those plugs will break down quickly and they actually will eat away at the mulch as they do.
Good luck with your lawn.
Belinda & Bobby