On Fri, 6 Jun 2008 14:52:07 -0700 (PDT), vxla
wrote:

What's the best way to install a window air unit into a 42" window in
a vintage apartment? Should I get some plywood pieces cut to fill the
gap between the unit and the window pane, or is there some other way
that is better?

Thanks.

I used 1" foil covered foam board over a couple 1X8 boards on each
end. Don't forget to seal the top of the window that is open.