19th leg: Friday 2/8/2002
MRLB to MRPA, Liberia to Palo Arco, Costa Rica
airport: Palo Arco
.7 hours

Costa Rica was very pretty but I don't think I got very impressive screenshots. 
20th leg: Saturday 2/16/2002
MRPA to MRBA, Palo Arco to Buenos Aires, Costa Rica
airport: Buenos Aires De Osa
1.2 hours

21st leg: Wednesday 2/20/2002
MRBA to MPDA, Buenos Aires, Costa Rica to David, Panama
airport: Enrique Malek Intl
.9 hours

22nd leg: Wednesday 2/27/2002
MPDA to MPMG, David to Panama City, Panama
airport: Marcos A Gelabert Intl
1.8 hours

I didn't actually see the Panama Canal on my way in so I went for a little sight-seeing trip later.
Panama Canal historical photos
A different Panama Canal site