We travel by car, so I can't offer much help with the airports, but this link might help you out http://lakeplacid.com/flash/planyourtrip/z-planyourtrip.htm . Major airports include Albany NY, Montreal and Burlington VT, but any one of those will put you 2 hours away from Lake Placid.
If you don't want to rent a car, I think one of your only options is to look at flying into Boston's Logan Airport and booking a connecting flight to Saranac Lake on Cape Air. That will put you about 15 miles from Lake Placid, which is an easy taxi ride. Just to let you know though, Cape Air has very small planes, I think they are commonly referred to as puddle jumpers.
Hmm... doesn't sound like it is gonna be an easy trip. Anyway, thanks a lot for your info Tammi.