"ERROR while getting interface flags: no such device"

To quote from the aircrack-ng site:

This means you have an old version of airmon-ng installed. Upgrade to at least v1.0-rc1.

They add chipset information/support in their newer releases, as well as incorporate patches.

To upgrade to the latest version of aircrack-ng, please follow the steps in this answer.

There are two possible reasons for this error I came through so far.

1. Device is in use: Kill all processes mentioned which could cause trouble, e.g.

   kill -9 3258 (kills your wpa_supplicant)

2. Update to latest aircrack-ng version: The documentation suggests to update to the latest version from svn.

If this does not help, you should provide more information/details on the issue.