Reset the motors
Rick has the right idea; if you won't be using the machine for awhile then shut the motor down. What you are hearing is not "air" but the motors being held in a static position at full power. This creates the "waterfall", "jet airplane", "air leak" noise. The only time the machine requires air is for clamping and plunging the blade. These sounds are in the ears of the beholder and can be loud or non descript white noise depending on other ambient noise and how good your hearing is. Mine is not that great so I'm not bothered by the motor noise, and there is lots of other noise in my work area.
Of course when you have full power to the motors for long periods of time they tend to get warm. We have never had a temperature exceed 120 F degrees under normal usage. Here again heat is something that in excess is bad for any product, but what is the temperature? 100 F degrees can feel "hot" but it is well within the range of the products operating temperature. Once again Rick's advice is sound; shut down the motors when not in use for long periods. If you have concerns please contact the Customer Services dept. for help, we are here for you.