The air stewardess was trying to do her job, but the airlines just have not thought about 'live worms' sitting in their seats!
My 2 yr old daughter cannot sit still for more than 3 minutes. For this reason, we have bought a 'sit n stroll' airline seat that also becomes a pram so it great for use in airports. Have a look at
www.sitnstroll.com, they are not very good looking, but are like a big comfy arm chair with a 5 point harness.
My daughter LOVES it, she sleeps really well in it and with the harness it means that she just cannot get out of the seatbelt. Weight limit is something like 16-18kg so we will be using it for a long time yet to come... Hope this helps!