Over the last couple of years Squaw has been giving out free lift tickets to the Military, they required the active duty ID card (including Reserves and Guard).
Chances are Northstar Ski Resort has the same rules. Sugar Bowl as of last year gave all military ID card holders 50% off, not sure about this year.

Each ski resort in the Lake Tahoe area has a web site with ticket discounts listed. For example, Mt Rose offers 2-for-1 on Tuesdays, Wednesdays is half off for those over 50, and Thursdays is Lady's day.

Another option for retired military is to call Fallon NAS rec center. They have deals and will mail you tickets. REI has deals for Tahoe also.

I've never tried the Airline ID for discounts at Tahoe because of all the local discounts available. You can PM me if you have questions about skiing Tahoe.