An oxygen concentrator is a machine that takes normal room air and, using a series of sieves, filters, and a compressor, removes nitrogen from the air, increasing the oxygen content of the resulting air to up to 96%.
Note: An oxygen concentrator is not to be confused with compressed oxygen which is prohibited on any JetBlue aircraft.
Specific models of oxygen concentrators are approved for onboard use as long as the customer meets the following requirements:
Link for Portable Oxygen Concentrators (POC) requirements