Yes. The OxyGo FIT Plus is approved by the FAA (Federal Aviation Administration) for use on an airplane. To confirm, you can look on the back or bottom of your unit for a sticker that looks like the following:
Example of an FAA-approval label. It may vary from make to model.
But, just because your POC is approved for in-flight use, you still need to be aware of other FAA, TSA, and airline requirements. Check out our blog post Can I fly with my portable oxygen concentrator for more information on flying with your POC.