Air Conditioner not blowing air

Hey everyone. First time posting but have long been a reader. My compressor turns on, and I can hear my furnace fan kick on, but no air comes out... sometimes. My filter is new, and I had a service man out to look at it and he checked everything out and couldn't find anything wrong, because of course the air was flowing just fine when he was here. I told him what was happening but he said he couldn't be sure unless he could see the problem as it occurred. Most times the air kicks on and blows just fine. But sometimes (more and more often recently) it kicks on, but nothing comes out. Same when I turn on just the fan. Most times when I shut everything off, wait 5 min, and turn it back on it will work, but not always. It's starting to take more and more time of shutting it on and off before it finally works. any ideas?

 

When no air comes out, is the furnace blower fan running at that time ? Did you see it running? or just heard the fan kick on.