I have travelled to KTM via Delhi once, and via Delhi to Bagdogra (INdia) once. Both the times, I have had a fine time, except for the interminable wait, and lack of any facilities (food, fun etc) in the airport.

However, coming back recently from KTM via Delhi, I saw the horrible ordeal one Nepali gentleman was put through for no reason I could comprehend. Once they find a pretext, they will start assembling folks who are strange: police, CRPs, but no knowledgeable immigrant expert in the airport. They just don't listen to you.

The ground staff of the airlines are just fine and helpful, even though the transit process is quite disorganized. If you have figured out the process, all is fine. First time: bad idea! If you do go through Delhi, make sure every baggage is marked for KTM. Also get your boarding pass right upto KTM from here, if possible. Coming back is tougher because KTM usually does not issue boarding passes beyond Delhi, and in Delhi, you hand over your PP to the airline staff and wait, and wait, and wait!

I guess I got off easy because I travel on US Re-Entry Permit.