Is there a reason that the IPv6 standard uses AAAA rather than AA? I cannot find reference to AA or AAA records in DNS. Do the As indicate anything specific?
RFC 1035, which defines resource records for DNS, mentions the meaning of record type A as 'host address'. 'Host address' back then was of 32 bits.
RFC 3596 explains the new resource record for IPv6. It defines a new record type to be used to store an IPv6 address.
So the new record type should signify the address that is stored with it. The best way to do that is to compare IPv6 with IPv4, and so we have four A's - four times that of the IPv4 length.