AOPA used to do AOPA Wings Insurance which was carried by Marsh.
Then suddenly, several years ago Marsh dropped the business with about 6 weeks notice, with no offer of re-insuring its existing customers (including me): even AOPA didn't know about it.
To give AOPA their due, I contacted Martin Robinson direct and he fixed me up with preferential rates with Besso (google 'em)
As already said, pre-existing LIFE policies (taken out before you started or had any intention to fly- important that last bit) are valid, but don't neglect the personal accident bit as well as the two are occasionally mutually exclusive.
In other words if you wipe yourself out while flying in USA (your policy is world-wide isn't it?), then your loved ones will pick up a tidy packet.
If however you injure yourself badly, need major surgery, spend weeks in hospital then get Medi-flighted back, you ain't covered.
Surprising how this aspect is un appreciated by many.
Cusco