No they detect stealth units the same as armor car and motor infantry.
Used to be they detected stealth units of equal or lower level but now you need to look at the info of the stealth army to see what level of stealth they provide at the army level they are at.
Stealth units are militia, commando, paratrooper, anti tank, and tank destroyer and submarine.
Interceptors cannot detect submarines. Only navy bombers and destroyers can detect those.
