Is the car seat flight safe? Has it been approved to be safe to use whilst flying?
The car seat is a very simple one, and I would not expect much of that. If it passed the requirements to be sold, it means it is safe enough to be sold, though there are no ADAC or OAMTC tests for this one, nor certificates for plane travel. You can take it on board though, and the basic safety measures are there. Nothing more.