Veteran's Day isn't really just 1 day. November 11th isn't the only day you can stop and thank someone for serving in the US military. It can be July 22nd when you thank someone. The fact is...you can thank a member of the US militar ANY day of the year. That simple thank you will mean something to them.
I've been part of a pen pal program with soldiers stationed overseas and most of them are so happy to receive letters, even if they are from people they don't know. It helps make life easier for them, helps them for a moment forget the hell they are going through. I'm related to a LOT of military members and I know just one small thank you means a lot to them. My father served. Both of my grandfathers did and even 2 of my uncles did. I've got a cousin who in a few months will be a member of the military. Trust me...your simple thank you does mean a lot to them.