I recently spent a bit of time figuring out how to best travel with my 8 month old - I ended up buying him a seat (1/2 price) and plan to carry a Graco Comfortsport seat.

I looked into the vests - although they are supposed to be useable on aircraft, the FAA regulations say they can not be used during take-off, landing, or moving on the ground (the most critical times!) - http://www.faa.gov/avr/afs/faa/8400/...3/3_016_06.pdf (see page 8)

I just hope they'll let me install the car seat rear facing as the FAA regulations say - I know some parents have had to fight for this too...

Audrey, mother to Graham