"For the busiest class C my guess is PDX, MKE, or MDW and for the busiest class D my guess is TEB or VNY. "
Here's a list of airports with Class C airspace-
Here's the Top 50 airports 'Ranked By Passenger Enplanments' in the U.S.-
Looks like MDW
is the busiest Class C based on enplanement criteria. Haven't located a 2004 ranking for airport operations to confirm on that criteria.
I'd also agree on VNY
because I have heard it's the busiest GA
airport, although again, I can't yet find a chart including GA
ops too so it can be confirmed statistically.
"Van Nuys Airport (VNY
) is ranked as the world's busiest general aviation airport. VNY
averages nearly one-half million takeoffs and landings annually, with 466,449 total operations in 2003."
"For the least busy class B I'd have to guess MSY or MCI."
is actually the lowest on the Top 50 list at #45 . MSY
is #38 & MCI