Portable car seats

[VelmaDaphne]

Does anyone have experience of this? I am taking my 6 year old and just-3 year old on holiday to Hamburg in a few weeks, and I'm nervous about negotiating public transport with them on my own (buses, tube etc). Looking at the map, the places we'll want to visit aren't that far from our hotel, and I'm wondering if a taxi might be easier. But there's the car seat issue. I've heard that you can buy inflatable care seats, and I wondered if anyone had ever used these.

[Hulababy]

Not got an inflatable one but we have a backpack car seat by Trunki which works very well. However, they are quite bulky so probaboy not great for having to walk around with.