CE mark dosn't mean its illegal to use only to sell in a eu shop.
You can use the GPS after takeoff when the fasten your seatbelt light is out. But you must turn it off when it turns back on again.
You will proberly have problems getting a clear signal unless you are in a window seat. Due to the shielding effect of sitting in the middle of a can.
Have fun. If its a British flight and you visit the flight deck see how close the position is compared to the LRNS.
MJ