My road bike has drop handlebars, and the horizontal part is flattened (ITM wing shape). Does anyone know of any clipon aerobars that will fit securely on those types of handlebars?
Look at Profile’s stem mounted aerobars. They should suit your needs.
Regards,
SD
I have ITM Wing Shape bars too. I can’t answer your question about aerobars but in a pinch, you can do a pretty good imitation by laying your forearms on the flat top of the bars and holding on to your Shimano shifter cables. I first tested this on a break-away attempt a few weeks ago and it actually was reasonably comfortable - all things considered 
I don’t think any of the common clip on bars have hardware that would fit that bar.