Yes, you can travel by plane with your keezel, but the device must be packed in your hand luggage and not your check-in luggage.
If you pack the keezel in your check-in luggage, you risk having it confiscated and destroyed because it contains a Lithium battery and these are not allowed in check-in luggage.
To be sure, we recommend always checking your airline's website for info about bringing devices with Lithium batteries on the plane.
If airport security asks you about the keezel's technical specifications, you can find these under the device's top-cap, which can be easily removed.
The info you'll find under the keezel's top-cap is:
FCC ID: 2AJFM-0001A
IC ID: 21612-0001A
BATTERY: LiPo 8200mAh