The TSA security people have no problem with portable oxygen concentrators. See this page for their ...

1. Can we carry on an oxygen concentrator in an airplanr?
The TSA security people have no problem with portable oxygen concentrators. See this page for
their regulations about those devices:
http://www.tsa.gov/traveler-information/...
HOWEVER, airlines have their own rules. For instance, for Delta:
"Delta also requires a medical certificate authorizing the use of an approved Portable Oxygen
Concentrator or confirming that a medical condition would not necessitate extraordinary medical
assistance during a flight."
See this for more info for Delta and look at the "On board Medical Oxygen" section:
http://www.delta.com/content/www/en_US/t...
Delta's web site seems to indicate that you can rent a portable concentrator for use on a plane, but
that requires some forms and significant advance notice to the airline
ALL airlines probably have their requirements, so you need to either call the one on which you are
flying, or look through their website for information.
https://answers.yahoo.com/question/index?qid=20141019133425AAauvZa