can I drag and drop files on to my ipad?

If you mean drop files from your computer to the ipad, then NO. You must go through itunes, unless the files are Pages or Numbers, or whatever files that can be put on icloud via the app that uses the files (e.g. pages for mac can save a pages file to icloud and then you can access the file from pages on iOS).

There are apps that will let you drag and drop files from the computer to the iPad. I have an app called File Manager Folder + that will let you drag and top files and also transfer them via WiFi. It's a pretty useful app actually.

Check it out here.

https://itunes.apple.com/us/app/file-manager-folder-plus/id484856077?mt=8

You also need to download an app on your computer, which is free, in order for this to work.