I noticed that air support makes changes to a few things for compatibility with air's application sandbox... would including jquery and using the jquery adapter break anything?
It's possible, but seeing that you are on AIR and there is no download to worry about, you are probably better off including both. This way you get the optimized Ext base lib for Ext functionality and jQuery for other spots you might need it.
Jack Slocum
Ext JS Founder
Original author of Ext JS 1, 2 & 3.
Twitter: @jackslocum jack@extjs.com