Google is testing displaying https and http in the URLs of AdWords ads.
Conrad O'Connell spotted this and posted a picture of the http in the display URL area of the ad and said Google is showing the https version as well for some ads. Conrad O'Connell posted the image on Twitter:
I was not able to replicate but I was able to show the ad with and without the www before the domain name:
Again, the HTTPS I was not able to replicate but it would not surprise me if Google does display HTTPS in the display URL for ads that lead to HTTPS landing pages.
Forum discussion at Twitter.