I think the best answer to this is simply, I don't know.
It seems it was not that long ago these 1964-66 Flair Birds were still in service, having outlasted plenty of other cars of that era. But sometime during the 1990's they disappeared suddenly, then just as suddenly they became collectible classics. I think we have a strange combination of things with these cars. First, they had a high level of desirability from the moment they were new, and when they went out of service many of them got put in garages or barns because they're "classics." But they are also expensive cars to restore, so in the barns they remain, with high hopes of someday gathering up the money it would need to restore them. So how many of these cars are survivors? A LOT. How many are on the road? A smaller percentage of that lot. As time goes by we see these barn finds exposed; someone brings home a new project that the original family finally decided to let go of. So as time goes by the number of drivable cars will probably increase. But how many are out there? Who knows. Then, how many are Landaus, convertibles, or such? Np way of telling. This seems to be true of the Flairbirds, more so than cars made either earlier or later. Strange group of cars.