Re: Taking inflatable PFDs on airplanes?
16 years ago I had my PFD cartridge removed and confiscated. It was a hassle to get a replacement at the other end. That was at the start of a 1700 mile trip with open ocean segments and I wasn't going without a working inflatable/harness.
Since then, I've noticed that TSA allows them, but, as someone else has stated, there may be different policies depending on the airline. So it doesn't hurt to check with your airline and print out their policy and the TSA's, just in case you need to make your case with an uninformed screener.
That said, I don't bother bringing my inflatable PFD to the Virgin Islands. We always try to restrict our luggage to one medium duffle and one carry-on per person for a 7-10 day charter, which can be a challenge. Leaving the PFDs behind is a practical matter, particularly if you expect to do any shopping at the other end and don't want to pay the fee for an additional bag.
If you feel the need for additional safety you might use the PFDs provided by the charter company. I've always found them to be clean and in excellent condition.