Yep, take it as carryon- if it won't fit in the overhead, they will stow it up front with the stewards <img src="i/expressions/face-icon-small-wink.gif" border="0"> . I have a set of luggage wheels for my Vest system, because it is too heavy for me to lug all over the airport. They do make you take it off the wheels to go through the security machine. My "wheels":
<a target=_blank class=ftalternatingbarlinklarge href="http://www.target.com/Black-Folding-Multi-Use-Cart/dp/B000BO8W50/qid=1213114146/ref=br_1_12/601-8051273-9741721?ie=UTF8&node=1042210&frombrowse=1&rh=&page=1">luggage cart</a>
And someone I was talking to yesterday/today got this one (I think this is it) to put the vest <i>and</i> the luggage on for the airport:
<a target=_blank class=ftalternatingbarlinklarge href="http://www.target.com/Flat-Folding-Multi-Use-Cart-Black/dp/B000BOACEO/qid=1213114229/ref=br_1_3/601-8051273-9741721?ie=UTF8&node=1042210&frombrowse=1&rh=&page=1">larger cart</a>
When they ask, I tell them it is a medical compressor- they will more than likely open it and use the "sniff" wand on it. If they are treating it kinda roughly, don't be afraid to tell them how much it cost <img src="i/expressions/face-icon-small-wink.gif" border="0"> . Have fun <img src="i/expressions/face-icon-small-smile.gif" border="0"> !