1) Bomdila, Dirang, Tawang
2) Itanagar, Ziro
3) Namdapha, Changlang
One can get the ILP for any one of the above sectors.
If you are visiting Bomdila sector, then the easiest way to reach there is by road from Tezpur (Assam). The nearest airport is Guwahati. One can then go to Tezpur by state transport buses. From Tezpur, shared vehicles are available every morning from 5:30 am. Make sure you book a nice seat with a reputed travel agency. Although the roads are good & maintained by Border Road Organization (BRO), but there are land slides in the rainy season.
If you are visiting Namdapha, then the nearest airport will be Dibrugarh (Assam).