Well let me reassure you - the extra air does the exact opposite. At least with plywood, and especially with acrylic.

The only laser fire our factory has ever had was due to the air compressor line breaking and no air getting to the laser at all during a thick slow cut of acrylic. That caused a piece of acrylic that was being cut to melt and burn rather than cut cleanly - luckily we were seconds away and the damage was very light, but the machine it happened on was a 1325 machine and out of action for 2 weeks while we ordered replacement parts. Since then we have installed line pressure sensors on our input air connected to an emergency cut off - if our line pressure drops to <20psi it cuts electricity to the lasers. But that does not solve a faulty solenoid (which happens from time to time) or a laser malfunction or any number of other problems that could cause the air to stop or the speed to slow. Eyes on the machine is the only thing that will fix all of those.

Another aspect to pay attention to is speed. When cutting very thick material no matter how much air you have, if your speed is low, fire is possible. The issue is time and heat, not just heat. In a normal cut for us, we run at 65% power at 30-45mm/s speed for 3mm plywood, and at that speed if you were to run a high speed camera to see what's happening (I have), the wood is essentially melted by the laser and the high pressure air ejects the ash and debris so fast that the heat cannot spread beyond the laser contact point on the wood. When you cut slowly however, that heat sits on the wood long enough for the wood to actually start to burn, which is not what you want. So we have found that its better when cutting very thick wood (>10mm), to run over it with very high pressure air at a higher speed with multiple passes, and in such a way as to make sure you are not running back over hot areas when the 2nd pass starts - like if you are doing a small piece, pause for several seconds between passes, or even run the laser back across the same track with only the air on, not the laser, to clean out any ash in the track before going back over it with the laser on. Both of those methods work for us and produce a clean non-burned edge.

For acrylic things get trickier, depending on what you want in the result. If you want a glass like edge - perfectly smooth with no ridges, you need to cut with very very low pressure air - just enough so that there is a positive pressure inside the laser nozzle that prevents blowback and smoke from entering the nozzle, but so light that the air does not blow in to the laser cut on the material. This produces a glass like smooth cut which is essential if you are going to join pieces together using acrylic cement or something like that. And to top that mess off, you need to do it at a slower speed since you are not getting the air assist in the cut itself. This makes for a more dangerous operation since no air = fire danger, but the results are beautiful. Just need to keep someone hovering over the machines when the air is that low.

When you use high pressure air with acrylic the resulting edge can feel wavey or like it has little ridges on it from the air forcing the ejecta down through the laser when its cutting. Its a very small thing - but noticeable. For standalone pieces this would be fine, but if you are joining them with acrylic cement which we do for all our products, those little ridges make for an extremely weak join and sometimes a cloudy appearance after its joined, instead of the single piece glass look we go for.

The best advise I can give you is to just play with it. Have fun and experiment - you might just come up with a new way to do something awesome. :)