Tere is a link to a site where you can find some of accessories for USA planes.
The names of firms could help you to find you need.
ACESSORIES FOR AMERICAN AIRCRAFT MODELS IN 1:32 SCALE
There some of the accessories from the site:
Grumman F-4F-4 Eduard 32109 Cockpit detaling, for Trumpeters Wildcat
Grumman F-4F-4 Verlinden 2073 Cockpit and gunbays, for Trumpeter Wildcat
Grumman F-4F-4 Cutting Edge Modelwork 32006 wheels,weighted, for F4F Wildcat
Curtiss P-40B Lone Star Models LSM Cockpit detail set.
Curtiss P-36 / Hawk 75 or P-40B Cutting Edge 32137 Cockpit super detail set with moulded on US Style seat belts.
Curtiss P-36 / Hawk 75 or P-40B Cutting Edge 32145 Cockpit super detail set with poseable on US Style seat belts.
I hope it would be helpful.