Better yet, try google:
Google:
http://www.google.com/search?hl=en&s...ar+seat&aqi=g1
First entry:
http://help.jetblue.com/SRVS/CGI-BIN...ase=obj(373795)
If checking a safety seat, it will not count as one of your checked bags and there is no fee assessed.
Also:
Use of booster seats, harness and vest restraints will not be allowed during the movement on surface, takeoff or landing, unless it is an FAA-approved device.
I'm presuming that "safety seat" to JetBlue means any seat that a child would use for safety purposes, which
could include car seats
and booster seats. If true, that's very cool.