USB drives formatted with FAT file system don't have such ownership issues, but once I've formatted my USB drive with ext4, and noticed that it's ownership changed to "root", as a result, I was not able to write anything to that device! I was frustrated, but found a solution that I am going to tell here as such thing could also happen when you format any USB drive with ext2.

• First, open your terminal, and then type "sudo NameOfYourFileManager" (for example, in KDE, type "sudo dolphin"), press "enter", give your sudo password. This will open your file manager with root privilege.
• Go to that device, right click and select "properties" from the drop down menu, then click the permission tab and you are there! Change the permission and ownership the way you want, close the window, you're done!

Sounds easy? It is. Try this, Good luck!