Check out http://www.airnav.com
for the frequencies of the airports.
CLE mainly sees 737s, DC-9s, ERJ-145s, and B-1900s. The best locations for viewing the planes are the CLE spectator deck at the end of Concourse B, and a dirt mound next to the 100th Bomb Group Restaurant.
CAK is more tricky. On a nice day, you will want to arrive at the airport around 2 PM on weekdays. It's only $4.00 for two hour parking at CAK. Upon arriving, head to the main terminal. There are plenty of windows and great locations to get pics. There should be a US Airways F100 either arriving or already there for their CAK-PIT-Richmond service. Around 2:30, AirTran's DC-9 should arrive. Also, there will be various other planes, such as NW S340s, or Comair's CRJs, or United Express's CRJ or Jetstream 41. Once the AirTran flight leaves, the terminal gets very empty, and the next planes won't arrive until 7-8 PM.