Well, after this summer's trip, and this past week's trip...here's my updated list:
(The first 4 are separate because I'm only 90% sure that I flew in/out of these airports)
CVG - Cincinnati, OH
SAV - Savannah, GA
PHL - Philadelphia, PA
BUF - Buffalo, NY
EWR - Newark, NJ
JFK - New York, NY
LGA - New York, NY
ACY - Atlantic City, NJ
BDL - Hartford, CT
AVP - Scranton, PA
MIA - Miami, FL
FLL - Fort Lauderdale, FL
MCO - Orlando, FL
ORD - Chicago, IL
MDW - Chicago, IL
CLE - Cleveland, OH
SLC - Salt Lake City, UT
LAS - Las Vegas, NV
LAX - Los Angeles, CA
LGB - Long Beach, CA
SAN - San Diego, CA
BUR - Burbank, CA
SFO - San Francisco, CA
IAH - Houston, TX
SJU - San Juan, PR
SEA - Seattle, WA
ATL - Atlanta, GA
BWI - Baltimore, MD
IAD or DCA - Washington, DC (can't remember)
MEM - Memphis, TN
DEN - Denver, CO
JAC - Jackson, WY
ABQ - Albuquerque, NM
DTW - Detroit, MI
MKE - Milwaukee, WI
HNL - Honolulu, HI
OGG - Maui, HI
ZRH - Zurich, Switzerland
YYZ - Toronto, ON, Canada
FCO - Rome, Italy
MXP - Milan, Italy
VCE - Venice, Italy
TLV - Tel Aviv, Israel
CDG - Paris, France
LHR - London, England
VIE - Vienna, Austria
FRA - Frankfurt, Germany
HKG - Hong Kong, China
PEK - Beijing, China
NRT - Tokyo, Japan
KBP - Kiev, Ukraine
AMS - Amsterdam, Netherlands
BCN - Barcelona, Spain
MAD - Madrid, Spain
Total: 54
And my flights just from the end of June through the end of September...LGA, ORD, JFK, HKG, PEK, NRT, HNL, OGG, HNL, LAX, JFK, LGA, MKE, SFO, MKE, LGA, CLE, LGA, JFK, AMS, KBP, AMS, JFK, EWR, ORD.
Modified using free WIFI on my A"A flight from EWR-ORD