Myidtravel allows adding the KTN in one section before you complete the booking but you cannot go and add it later. Are you unable to add it directly on the AF website? That has been my back up if I forget to add it manually while booking (if there is a way to save it, I haven't found it). There is a document section while booking that you can skip without adding anything or even choosing "skip this section" so it is easy to miss the place to put in the KTN.
Bookmarks