You’re not allowed to fly with any battery larger than 160wh capacity, and even then the battery needs to be in hand luggage, ie with you in the plane cabin and not in hold baggage.
That mondraker use the tq hpr 50 motor, the main battery is 360wh,so too large to take on a plane, but the range extender battery is only 160wh,so you can take the bike without the main battery, and just take the range extender in hand luggage.
I did this with my trek fuel exe that has the same motor system as your mondraker when I went to Spain last year.