I remember a radio interview conducted during WWE's RAW tour of Europe in 2003 that Flair was a guest on promoting it, he said he was really a 23-time world champion altogether, but they cut it down to 16 because it would be easier to follow since some of the unrecognized title changes happened within the same week and weren't even televised and / or recorded.
so Flair's "official" world title history (I copied and pasted this to my comp off WWE.com a long tme ago):
NWA World Heavyweight Championship (8 Times)
def. Dusty Rhodes, Sept. 17, 1981
def. Harley Race, Nov. 24, 1983 [starrcade]
def. Kerry von Erich, May 24, 1984
def. Dusty Rhodes, Aug. 7, 1986
def. Ron Garvin, Nov. 26, 1987 [starrcade]
def. Ricky Steamboat, May 7, 1989 [Wrestle War]
def. Sting, Jan. 11, 1991
def. Barry Windham, July 18, 1993 [beach Blast]
WCW Championship (6 Times)
def. Vader, Dec. 27, 1993 [starrcade]
def. Randy Savage, Dec. 25, 1995 [starrcade]
def. Randy Savage, Feb. 11, 1996 [superbrawl VI]
def. Hollywood Hogan, March 14, 1999 [uncensored]
def. Jeff Jarrett, May 15, 2000 [Monday Nitro]
awarded to by "WCW Commisioner" Kevin Nash, May 29, 2000 [Monday Nitro]
WWF Championship (2 Times)
by winning the 1992 Royal Rumble on Jan 19th
def. Randy Savage, Sept. 1, 1992