I haven't traveled with a nebulizer in a long time but they sometimes would ask what it was shouldn't be a problem. They may want you to turn it on. I'd make sure the Epi-Pen has the prescription information on it. As long as the Aero-bed fits in a carryon should be okay.
Thousands of people fly with nebulizers every day. They see them all the time, know what they are, and don't give them a second glance. Same thing with Epi-Pens, rescue inhalers, insulin syringes and pumps, breast pumps, CPAP machines, and a host of other medical devices.