We struggled through a good half dozen haircuts with our son on our own. We always had to stop early* when he cried too much for us to bear.
His most recent haircut (21 months) was by far the best yet. We actually used a Flowbee (yes, the as seen on tv product from the '90s!) He sat in front of the tv, we cut his hair with the Flowbee, and the vacuum took care of the trimmings.
For those unfamiliar, it's a shaver attachment that connects to a vacuum cleaner. It has various tubes that keeps the cutting blades a certain distance away from the scalp. The vacuum sucks the hair straight and into the blade, gobbling up all the cut hair as well.
Finally no more cries of "eyes itchy!"
The Flowbee is more expensive than we expected. It was about $130 on Amazon. But I'll probably get my own haircuts with it too, so it'll save money in the long run. And hundreds of reviews gave it 4.5 stars!
The biggest complaint we have is how loud the bugger is. We had to do a lot of coaxing to ease him into the thing. Letting him flip the switch to turn it on helped. We also never got too close to the ears, due to the volume. But it's definitely a lot louder than we anticipated.
* I had to try really hard not to use the pun "cut it short" here